Top 10 Best Spark Plugs for Older Engines That Boost Power!

Older engines often come with unique challenges when it comes to maintaining performance and fuel efficiency. Over time, spark plugs can wear out or become less effective, causing issues like rough idling, reduced power, and increased emissions. Finding the best spark plugs for older engines can help restore smooth operation and extend the engine’s lifespan.

Finding the best spark plugs for older engines can help restore smooth operation and extend the engine’s lifespan. This review focuses on spark plugs designed specifically for vehicles with higher mileage or vintage models. These plugs offer improved ignition reliability, better combustion, and resistance to fouling, which are key factors for older engines that may have accumulated deposits or wear in their cylinders.

Here, you’ll find detailed information on top options available, including their features, durability, and compatibility. Whether you want to replace your current plugs or upgrade to something better suited for an aging engine, this guide will provide practical advice to help you make an informed choice.

Revitalize Your Classic Ride with Top-Performing Ignition Solutions

Image	Product	Price
Pick 1	AC Delco R45TS Spark Plug Set of 8	Check Price
Pick 2	NGK G-Power Platinum Spark Plugs TR5GP – 8 Pack	Check Price
Pick 3	Briggs & Stratton 796112 Spark Plug 2-Pack	Check Price

1. AC Delco R45TS Spark Plug Set of 8

Experience reliable engine starts every time with the AC Delco R45TS Spark Plug Set of These plugs bring a precise spark to older GM vehicles, promoting smooth combustion and consistent performance. Designed with quality and endurance in mind, they help keep your engine running efficiently through varying driving conditions.

Manufactured to match original equipment standards, these spark plugs are an ideal replacement for Chevrolet, Buick, GMC, and Cadillac models. Whether you’re navigating city traffic or hitting the highway, they support dependable ignition and enhanced fuel efficiency for your older engine.

Each AC Delco R45TS spark plug is engineered to ignite the fuel mixture accurately within the combustion chamber. This ensures smooth engine starts and steady firing, reducing misfires and improving overall engine response. Made to meet GM OE specifications, you receive a product built for compatibility and performance reliability.

The plugs are crafted with durable materials that withstand the demands of frequent driving, including stop-and-go traffic and long-distance trips. Their design supports better ignition timing, contributing to improved fuel economy and lower emissions. Installation is straightforward, which makes servicing your older engine simpler and hassle-free.

Ideal for owners of older GM vehicles, this set of eight covers multiple cylinders, offering a complete solution for maintenance or restoration projects. The product balances build quality with affordability, making it a smart investment for extending your engine’s lifespan without compromising performance.

Pros

• Manufactured to meet GM original equipment standards
• Supports efficient ignition and improved fuel economy
• Durable design suitable for city and highway driving conditions

Cons

• Specific fitment limited to certain GM vehicle models

The AC Delco R45TS Spark Plug Set provides a dependable and high-quality replacement for older GM engines. By maintaining OEM standards, it ensures consistent ignition performance, making it a reliable choice for regular maintenance or vehicle restoration.

Compared to generic spark plugs, AC Delco offers tailored compatibility and trusted durability for lasting results.

2. NGK G-Power Platinum Spark Plugs TR5GP – 8 Pack

NGK G-Power Platinum Spark Plugs TR5GP deliver reliable ignition performance for older engines. Their platinum construction and advanced design help maintain strong combustion over long periods. These plugs are crafted to resist carbon buildup and provide consistent power output, enhancing engine smoothness.

Designed to fit a broad heat range, they prevent pre-ignition and improve fuel efficiency. The patented triple gasket sealing process eliminates combustion gas leaks.

Perfect for vehicles needing dependable ignition replacements without sacrificing quality.

These spark plugs utilize platinum technology to support longer service life and enhanced durability. They operate effectively within a wider heat range compared to standard plugs, ensuring stable engine performance across diverse conditions. Carbon buildup resistance reduces maintenance needs, keeping the engine cleaner over time.

Built with precision, their triple gasket seal prevents combustion gas leakage, maintaining optimal pressure inside the cylinder. This reduces misfires and promotes smoother ignition with every start. The 8-pack offers multiple replacements, making it convenient to keep your vehicle running efficiently.

The 8-pack offers multiple replacements, making it convenient to keep your vehicle running efficiently.

Known for consistent reliability, these plugs suit drivers maintaining older engines requiring stable ignition components. Their design fits various OEM part numbers, broadening compatibility across different models. Installation is straightforward, making them accessible for routine engine upkeep.

Pros

• Wide heat range for versatile engine compatibility
• Patented triple gasket seal prevents combustion gas leaks
• Resists carbon buildup, enhancing longevity and performance

Cons

• May require careful selection to match specific engine models

The NGK G-Power Platinum Spark Plugs stand out as dependable ignition components for older vehicles. Their advanced features and ease of installation make them a practical choice for maintaining engine efficiency.

3. Briggs & Stratton 796112 Spark Plug 2-Pack

The Briggs & Stratton 796112 Spark Plug 2-Pack offers reliable ignition performance for older engines. Designed to fit a wide range of small engines, these spark plugs deliver consistent power and efficiency.

Maintaining optimal engine function becomes easier with these durable spark plugs. Their high-quality construction supports longer-lasting performance under tough conditions. Ideal for lawn mowers, garden equipment, and other machinery with older engines.

Ideal for lawn mowers, garden equipment, and other machinery with older engines.

Built by Briggs & Stratton, these spark plugs model 796112-2pk replace the OEM J19LM part number. Each pack contains two units, ready to install on compatible engines enhancing ignition reliability.

The plugs are engineered to meet manufacturer specifications for consistent operation and longevity.

They feature sturdy construction that withstands heat, vibration, and wear over extended use periods. This durability helps prevent misfires, promoting smoother starts and better fuel efficiency. Users will find installation straightforward without the need for special tools or adjustments.

Users will find installation straightforward without the need for special tools or adjustments.

These plugs rank highly among lawn mower spark plugs, reflecting strong user satisfaction and proven performance. They suit older engines requiring spark plugs that replicate original equipment quality closely. Compared to generic alternatives, these retain tighter tolerances and superior combustion support.

Pros

• Replaces OEM J19LM plug with exact fit and function
• Durable design resists heat and engine vibration
• Easy installation with two plugs included per pack

Cons

• Limited to specific Briggs & Stratton engine models

Offering dependable ignition tailored for older engine models, the Briggs & Stratton 796112 Spark Plug 2-Pack provides lasting value and ease of replacement. Their trusted design supports equipment longevity and steady performance over time.

4. ACDelco 41-962 Platinum Spark Plug Set

ACDelco 41-962 Platinum Spark Plug Set offers a reliable upgrade for older engines needing enhanced ignition performance. Designed to deliver consistent spark and long-lasting durability, these spark plugs help maintain engine efficiency and smooth operation.

Ideal for vehicles requiring professional-grade components, this set combines advanced materials and construction techniques to reduce wear and interference. Experience improved engine response and fewer misfires with these durable spark plugs.

The ACDelco 41-962 spark plugs feature a one-piece, fired-in suppressor seal that blends three types of glass. This gas-tight seal effectively reduces radio frequency and engine interference, which supports a steady spark plug energy flow.

Additionally, it protects against compression pressures, extending the lifespan of the spark plug. The center and ground electrodes are equipped with double platinum point pads. This design offers excellent durability while meeting consistent voltage requirements, resulting in reduced wear on the ignition system components.

A pure copper core enhances heat conductivity, keeping the electrodes cooler. Cooler electrodes increase resistance to fouling and prolong the spark plug’s service life.

Manufactured to match or exceed original equipment specifications, these spark plugs are engineered for smooth starts and a reliable combustion process. The installation process is straightforward, fitting most older engine models with ease. This set is a perfect choice for drivers seeking to maintain engine performance without frequent replacements.

This set is a perfect choice for drivers seeking to maintain engine performance without frequent replacements. It balances quality and efficiency, making it suitable for those who want dependable ignition parts that support long-term vehicle reliability.

Pros

• Durable double platinum electrodes provide long service life
• Suppressor seal reduces engine interference and voltage loss
• Copper core enhances heat dissipation and fouling resistance

Cons

• May require periodic inspection to maintain optimal performance

For owners of older engines seeking dependable, high-quality spark plugs, the ACDelco 41-962 set delivers durability and steady ignition performance. These plugs stand out by combining advanced materials with solid construction, making them a trustworthy option for maintaining engine health over time.

5. NGK Iridium IX Spark Plug LKR7DIX-11S 4 Pack

The NGK Iridium IX Spark Plug LKR7DIX-11S 4 Pack is designed to enhance the performance of older engines with precision and durability. Its ultra-fine iridium tip and advanced materials provide reliable ignition and smoother acceleration.

Ideal for drivers seeking consistent engine response, these plugs deliver lasting spark stability and are built to handle demanding conditions with ease.

NGK’s Iridium IX spark plugs feature a 6 mm fine iridium tip that offers remarkable ignitability, improving throttle response and acceleration. The tapered ground electrode reduces quenching, which allows for stronger and more stable flames inside the combustion chamber. Each plug incorporates a longer insulator with corrugated ribs that help prevent flashover, while a triple gasket seal eliminates combustion gas leakage for optimal performance.

Constructed with iridium alloy, these plugs withstand high temperatures and electrical wear, making them highly durable for extended use. The trivalent metal plating adds effective anti-corrosion and anti-seizing properties, ensuring easier removal and maintenance. Designed to fit many older engine models, their quality and design maximize fuel efficiency and engine smoothness.

Designed to fit many older engine models, their quality and design maximize fuel efficiency and engine smoothness.

Users will appreciate the balance of performance and longevity offered by these spark plugs. With a resistor value of 5K ohms and a 5/8 inch hex size, installation is straightforward. Compared to standard plugs, NGK Iridium IX stands out with its fine-wire technology, contributing to a lifespan of 40,000 to 60,000 miles under typical driving conditions.

Compared to standard plugs, NGK Iridium IX stands out with its fine-wire technology, contributing to a lifespan of 40,000 to 60,000 miles under typical driving conditions.

Pros

• Excellent ignitability with ultra-fine 0.6 mm iridium tip
• Durable construction suited for high heat and electrical wear
• Features anti-corrosion plating for easier maintenance

Cons

• May require verification of compatibility for very specific older engines

NGK Iridium IX spark plugs deliver a reliable and efficient ignition solution tailored for older engine models. Their performance advantages and durability make them a worthwhile upgrade to preserve engine responsiveness and longevity.

6. ACDelco CR43TS Conventional Spark Plug – Pack of 8

Experience reliable ignition and improved engine performance with the ACDelco CR43TS Conventional Spark Plug. Designed specifically for older engines, this pack of eight plugs offers durability and consistent power delivery to keep your vehicle running smoothly.

Ideal for automotive and marine use, it combines advanced materials with thoughtful design to extend engine life.

Each spark plug features a copper core that enhances heat transfer and durability, making them suitable for demanding conditions. The ribbed suppressor seal reduces spark flash-over and misfire, ensuring steady ignition every time.

These spark plugs are built to withstand marine applications, offering versatility beyond standard automotive use. Installation is straightforward, allowing for quick replacement to optimize engine efficiency.

The ACDelco CR43TS plugs balance performance and value, making them a practical choice for those maintaining older vehicles. Suitable for drivers seeking dependable ignition components, these plugs provide a consistent spark that enhances overall engine smoothness and fuel efficiency.

Pros

• Copper core improves heat transfer and durability
• Ribbed suppressor seal prevents misfire and flash-over
• Black onyx coating resists corrosion for longer life

Cons

• Conventional design may not match performance of iridium or platinum options

The ACDelco CR43TS spark plugs provide solid performance and reliability for older engines. Their durable construction and resistance features make them a dependable choice that offers great value for everyday use.

7. NGK Iridium Spark Plugs LFR6AIX-11 (6 Pack)

NGK Iridium Spark Plugs LFR6AIX-11 (6 Pack) offer exceptional performance for vehicles with older engines. Crafted to withstand a wider heat range, these spark plugs deliver reliable ignition and enhanced durability. They resist carbon buildup and reduce pre-ignition, promoting a smoother engine operation.

They resist carbon buildup and reduce pre-ignition, promoting a smoother engine operation.

Each spark plug features a patented triple gasket sealing process that prevents combustion gas leakage and protects engine components. Designed with high-grade iridium, they provide a longer lifespan compared to standard plugs.

Built by NGK, a reputable name in ignition systems, these spark plugs replace several OEM models, offering wide compatibility with various car makes. Their iridium tips enable a fine electrode design that improves spark precision and fuel efficiency, making them ideal for older engines needing a reliable upgrade.

Thanks to the triple gasket seal, combustion gases remain contained, enhancing engine power and reducing emissions. Installation is straightforward and fits standard spark plug sockets without additional tools or adjustments. Their superior build quality promises longevity, saving time and effort on frequent replacements.

Their superior build quality promises longevity, saving time and effort on frequent replacements.

This 6-pack provides excellent value for anyone maintaining or restoring older vehicles. The plugs’ advanced material composition and engineering contribute to smoother starts, better throttle response, and overall improved engine performance. They work well for daily drivers and classic cars requiring dependable ignition components.

They work well for daily drivers and classic cars requiring dependable ignition components.

Pros

• Long-lasting iridium tip improves durability and performance
• Patented triple gasket sealing prevents combustion gas leaks
• Reduces carbon buildup and pre-ignition in older engines

Cons

• Some users may find installation challenging on uncommon engine types

NGK Iridium Spark Plugs LFR6AIX-11 stand out as reliable replacements for older engines. Their durable construction and efficient design deliver consistent ignition and extended plug life, making them a practical choice when upgrading or maintaining an aging vehicle’s ignition system.

8. Briggs & Stratton 491055 Spark Plug 2-Pack

Briggs & Stratton 491055 Spark Plug 2-Pack delivers reliable ignition performance for a smooth start every time. Designed to fit a wide range of older engines, these spark plugs maintain engine efficiency and prolong engine life.

Whether you’re maintaining lawn mowers or outdoor equipment, they provide consistent results.

These spark plugs are engineered to meet or exceed original equipment specifications. The two-pack offers convenience for replacing multiple plugs without extra purchases.

Their compatibility with older engines makes them an excellent replacement option that supports engine longevity. Installing the plugs is straightforward thanks to standard sizing and design, allowing a hassle-free swap that keeps your equipment running at peak performance.

Built by Briggs and Stratton, a trusted name in outdoor power equipment, these spark plugs guarantee quality and consistency. The 491055 model number aligns perfectly with many small engine models, offering seamless fit.

Compared to many generic alternatives, these plugs provide better durability and spark reliability, enhancing overall engine function. Their lightweight design facilitates simple handling during installation and replacement, saving time for users.

Ideal for homeowners and professionals maintaining older engines, these plugs support extended engine life and help maintain performance standards over time.

Pros

• Compatible with a wide range of older engines for versatility.
• Durable construction that resists wear and fouling.
• Provides reliable ignition for smooth starts and steady engine operation.

Cons

• Limited to specific engine models; double-check compatibility before purchase.

The Briggs & Stratton 491055 Spark Plug 2-Pack stands out as a dependable and efficient choice for maintaining older engines. It offers reliable ignition performance while supporting engine longevity and efficiency. These spark plugs make a practical investment for keeping equipment running smoothly.

9. Briggs & Stratton 496018 Spark Plug (2 Pack)

Enhance the performance of older engines with the Briggs & Stratton 496018 Spark Plug (2 Pack). Designed to fit a variety of lawn and garden equipment, these spark plugs restore reliable ignition.

Their trusted OEM equivalent quality ensures consistent engine starts and smooth operation.

Perfect for those maintaining or repairing older engines, these spark plugs deliver dependability and endurance. With two plugs in one pack, you get great value and convenience for essential maintenance tasks.

A reliable ignition system is critical for older engines, and the Briggs & Stratton 496018 Spark Plug excels in delivering just that. Each plug features precise engineering to meet factory specifications, ensuring a proper fit and optimal combustion. The rust-resistant materials contribute to longevity under regular use.

Installation is straightforward as these plugs match OEM dimensions, allowing an easy replacement process. Its heat range suits a variety of older engine models, reducing fouling and improving fuel efficiency.

The 2-pack provides a cost-effective solution for replacing multiple plugs or keeping a spare handy.

Users will appreciate consistent performance across different conditions, including start-up and steady operation. This spark plug performs well in gasoline engines found in lawnmowers, generators, and other small engines. For those focused on dependable maintenance, these plugs offer a solid balance of quality and durability.

Pros

• OEM equivalent design ensures easy fit and reliable ignition.
• Durable materials resist corrosion for extended service life.
• Pack of two offers good value and convenience.

Cons

• Specific fit limits compatibility to certain older engine models.

The Briggs & Stratton 496018 Spark Plug (2 Pack) is a dependable choice that revitalizes older engines with quality ignition performance. Its simple installation and proven durability make it a practical pick compared to generic alternatives, ensuring your equipment keeps running smoothly season after season.

10. NGK Iridium IX DCPR7EIX Spark Plugs for Harley Davidson Twin Cam

NGK Iridium IX DCPR7EIX Spark Plugs deliver exceptional ignition performance designed specifically for Harley Davidson Twin Cam engines. Their advanced iridium technology ensures reliable starts and consistent power output every time.

Ideal for older engines, these spark plugs improve efficiency and extend ignition system life.

These plugs come pre-gapped for easy installation, allowing a seamless upgrade without additional adjustments. The ultra-small diameter center electrode minimizes voltage needs, providing smoother engine operation and better fuel combustion. Built with durable materials, they resist corrosion and wear over long periods of use.

NGK’s industry-leading spark plug design offers enhanced ignition quality tailored for Harley Davidson Twin Cam models from 1999 to The iridium center electrode is thinner and harder than standard plugs, promoting quicker, more reliable sparks. This reduces misfires and increases throttle response for a more enjoyable ride.

This reduces misfires and increases throttle response for a more enjoyable ride.

The metal shell plating includes improved anti-corrosion properties, protecting the spark plugs against harsh environmental conditions. Each pack contains two plugs that come pre-gapped for hassle-free replacement. Their lightweight construction also contributes to consistent engine performance without adding burden.

These spark plugs are best suited for owners looking to maintain or restore older Harley Davidson motorcycles. They provide a cost-effective option to boost ignition reliability and engine efficiency.

Pros

• Pre-gapped for immediate installation and optimal performance
• Ultra-small iridium center electrode reduces voltage demands
• Enhanced corrosion resistance extending spark plug lifespan

Cons

• Specifically designed for Harley Davidson Twin Cam, limiting compatibility

Overall, the NGK Iridium IX DCPR7EIX spark plugs offer reliable and efficient ignition upgrades for older Harley Davidson Twin Cam engines. Their durable construction and advanced design help maintain engine performance while reducing maintenance frequency.

These plugs stand out compared to standard options by delivering smoother starts and longer service life.

Things to Consider Before Buying Best Spark Plugs for Older Engines

Engine compatibility

Checking spark plug fitment for older engines involves understanding the specific design and operational characteristics that these engines require. Different engine types can have varying combustion chamber shapes, heat ranges, and thread sizes, all of which influence the ideal spark plug choice. It helps to identify the engine’s make and model to determine the characteristics that align with its design requirements, such as the electrode type and heat dissipation ability.

Verifying manufacturer recommendations provides a reliable guide, as these specifications are developed based on extensive testing to ensure compatibility and performance. Adhering to these guidelines can help maintain engine efficiency and smooth operation, making certain that the spark plugs work harmoniously with the existing engine components without causing undue wear or inefficiency.

Material and construction

Copper spark plugs are known for their excellent conductivity, making them effective at igniting fuel in older engines that do not require high heat tolerance. These plugs tend to wear out faster due to the softer metal but offer good performance during cold starts. Platinum spark plugs strike a balance by providing enhanced durability and better resistance to heat compared to copper, making them suitable for engines that experience moderate stress.

Iridium spark plugs are the most durable and possess superior heat resistance, which helps prevent fouling and extends their lifespan significantly. Corrosion resistance varies among these materials, with iridium and platinum generally faring better against wear from combustion byproducts and environmental factors.

Choosing the right construction can impact how well the engine performs, how often spark plugs need replacement, and how efficiently the engine runs over time.

Heat range and performance

Heat range plays a significant role in determining how well spark plugs perform in older engines, as it affects the plug’s ability to dissipate heat efficiently. Selecting a spark plug with a heat range that matches the engine’s operating conditions helps in achieving smoother starting and better fuel efficiency, as plugs that run too hot can cause pre-ignition while those running too cold may foul more quickly.

Balancing the heat range ensures the spark plugs provide consistent ignition without causing damage, helping to protect the engine from excessive wear and maintaining reliable performance over time. This understanding contributes to maintaining older engines in good running order by supporting efficient combustion and preventing potential mechanical issues associated with incorrect spark plug temperatures.

Electrode design and gap

The shape and size of a spark plug’s electrode play a significant role in how effectively an older engine ignites the air-fuel mixture. A well-shaped electrode facilitates a strong and consistent spark, which directly impacts combustion quality and engine performance. For older engines, the spark plug gap—the distance between the center and ground electrodes—requires careful adjustment to match the engine’s specifications and wear patterns.

For older engines, the spark plug gap—the distance between the center and ground electrodes—requires careful adjustment to match the engine’s specifications and wear patterns. Properly setting this gap helps maintain efficient ignition, leading to smoother starts and more reliable operation. If the gap is too wide or too narrow, it can cause misfires or incomplete combustion, reducing engine efficiency and potentially increasing emissions.

Paying attention to these details helps preserve the longevity of older engine components while keeping performance steady over time.

Brand reputation and warranty

Trusted brands for vintage and older engines often have long-standing histories of producing reliable and durable spark plugs. Reliability feedback from users provides valuable insights into how these spark plugs perform over time under the specific conditions faced by older engines.

Customer reviews highlight not only the effectiveness of the spark plugs in maintaining engine performance but also the service experience, which can be an important factor for those maintaining vehicles with aged components. Choosing spark plugs from brands known for their dedication to quality and support usually results in a more dependable and satisfying ownership experience.

Cost and availability

Balancing price with quality and longevity plays a big role when choosing replacement spark plugs for older engines. Often, parts made specifically for older models are less commonly stocked, making availability a factor to keep in mind.

Considering the trade-offs between the assurance of OEM parts and the cost-effectiveness of aftermarket plugs helps in making a decision that suits maintenance needs and the expected life span of the spark plugs. Checking suppliers that specialize in vintage or classic vehicle components can improve access to suitable products for older engines.

Quality materials and correct heat ranges also contribute to extending the service interval, reducing the frequency of replacements and overall maintenance expenses.

FAQ’s

What Are The Best Spark Plugs For Improving Performance In Older Engines?

The best spark plugs for improving performance in older engines are usually high-quality iridium or platinum plugs, as they offer better durability and more consistent spark. Additionally, selecting plugs with the correct heat range and gap size for your specific engine is essential to optimize efficiency and power.

How Do Spark Plug Materials Affect The Performance Of Vintage Or Classic Car Engines?

Spark plug materials impact vintage or classic car engines by influencing ignition efficiency and durability; for example, platinum or iridium plugs provide better spark consistency and longer life compared to traditional copper. Using the appropriate material helps maintain optimal engine performance and reduces maintenance frequency.

Are There Specific Spark Plug Brands Recommended For Older Engine Models?

Yes, specific spark plug brands like NGK, Bosch, and Denso are often recommended for older engine models due to their reliable performance and compatibility. It’s best to consult the vehicle’s manual or a trusted mechanic to choose the right brand and type for your engine.

What Factors Should Be Considered When Choosing Spark Plugs For An Engine Over Years Old?

When choosing spark plugs for an older engine, consider the engine’s make, model, and manufacturer specifications, as well as the plug’s heat range and durability to ensure proper combustion and avoid damage. Additionally, evaluate the wear and deposits on existing plugs to select materials that match the engine’s condition and driving habits.

How Often Should Spark Plugs Be Replaced In Older Engines To Maintain Optimal Performance?

In older engines, spark plugs should typically be replaced every 30,000 to 50,000 miles to maintain optimal performance. However, it’s important to check the manufacturer’s recommendations and inspect the plugs regularly for wear or deposits.

Conclusion

Choosing the right spark plugs can greatly affect an older engine’s performance and longevity. The best spark plugs for older engines offer improved ignition reliability, better fuel efficiency, and reduced emissions, helping maintain smooth engine operation despite aging components. While some options may require more frequent replacement or a higher upfront cost, their benefits in restoring engine responsiveness often outweigh these drawbacks.

While some options may require more frequent replacement or a higher upfront cost, their benefits in restoring engine responsiveness often outweigh these drawbacks. These spark plugs are particularly suited for drivers aiming to enhance their vintage or high-mileage vehicles without extensive modifications. For those seeking a practical upgrade to support an aging engine’s upkeep, investing in high-quality spark plugs designed specifically for older engines is a sensible and effective choice.

This approach balances performance and durability, making it easier to keep older vehicles running well.