Choosing the Right Spark Plugs for Your 1985-1995 Toyota MR2
A detailed guide to selecting the best new aftermarket spark plugs for your AW11 or SW20 MR2.
- Stick with NGK or Denso brands for the best reliability and performance in your MR2.
- Identify your specific engine (4A-GE, 3S-GTE, etc.) to ensure you purchase the correct plugs.
- For modified 3S-GTE turbo engines with increased boost, use a colder heat range plug (like NGK BKR7E) to prevent engine damage.
- Avoid budget brands like Autolite and Champion, as they are known to cause issues in these engines.
Understanding Your MR2's Engine
Before buying spark plugs, you must know which engine is in your MR2. The 1985-1995 model years cover two different generations with different engines, which use different plugs.
- AW11 (1985-1989): This first generation primarily uses the 4A-GE (1.6L naturally aspirated) or the 4A-GZE (1.6L supercharged) engine.
- SW20 (1990-1995): This second generation uses the 5S-FE (2.2L naturally aspirated) or the 3S-GTE (2.0L turbocharged) engine in the North American market.
Pro Tip: Always verify your specific engine before purchasing. The wrong spark plug can cause poor performance or even engine damage.
Symptoms of Failing Spark Plugs
When your MR2's spark plugs are worn out, you will notice it in how the car drives. Common signs include:
- Rough Idle: The engine may shake or vibrate more than usual when stopped.
- Engine Misfires: You might feel a hesitation, stutter, or jerking during acceleration. This is especially noticeable under boost in a 3S-GTE.
- Poor Acceleration: The car may feel sluggish or less responsive than normal.
- Reduced Fuel Economy: Worn plugs cause inefficient fuel burn, meaning you'll make more trips to the gas station.
- Difficulty Starting: A weak spark can make it hard for the engine to turn over, especially in cold weather.
- Check Engine Light: On later SW20 models, a failing spark plug can trigger a Check Engine Light with codes like P0301, P0302, etc., indicating a misfire in a specific cylinder.
Choosing the Right Aftermarket Spark Plug
For Toyota engines, the brand of spark plug matters. Owner communities and mechanics strongly recommend sticking with the original Japanese brands, which often perform better and are more reliable in these cars than other options.
Brand Quality Tiers for the MR2
Tier 1: Highly Recommended (OEM Quality or Better)
- NGK: This is the most widely recommended brand for all MR2 engines. They are known for reliability and performance. The BKR-series is the go-to for the 3S-GTE, while the BCPR-series is common for the 4A-GE.
- Denso: Denso is part of the Toyota group and is often the original equipment (OEM) manufacturer. They are an excellent, reliable choice and are considered equal in quality to NGK.
Tier 2: Use with Caution
- Bosch: While a major brand, Bosch plugs are generally seen as a better fit for European vehicles. Some MR2 owners have used them without issue, but they are not the community-preferred choice.
Tier 3: Not Recommended for MR2
Brands like Autolite and Champion are frequently associated with poor performance, misfires, and short lifespans in Japanese engines by owners on forums and Reddit. It is best to avoid these brands for your MR2.
Spark Plug Material: Copper vs. Iridium/Platinum
The material of the spark plug tip affects its price, performance, and lifespan.
- Copper: Copper plugs are very inexpensive and offer great performance. However, they wear out very quickly, often needing replacement every 5,000-15,000 miles. Many turbo MR2 owners prefer cheap NGK copper plugs and simply change them with every oil change to ensure peak performance.
- Iridium & Platinum: These are 'long-life' plugs, often lasting 60,000 miles or more. They are more expensive upfront but require less frequent changes. For a daily-driven, non-modified car, they are a great 'set it and forget it' option.
| Engine | Condition | Recommended Plug | Material |
|---|---|---|---|
| 4A-GE (AW11) | Stock | NGK BCPR6ES-11 or Denso equivalent | Copper |
| 3S-GTE (SW20 Turbo) | Stock / Light Mods | NGK BKR6E or BKR6EIX | Copper or Iridium |
| 3S-GTE (SW20 Turbo) | Higher Boost (14+ psi) | NGK BKR7E or BKR7EIX | Copper or Iridium |
| 5S-FE (SW20 N/A) | Stock | NGK BKR6EGP or Denso equivalent | Platinum |
Turbo Tip: For the 3S-GTE engine, if you have increased the turbo boost pressure, you should use a 'colder' spark plug. The NGK '7' heat range (e.g., BKR7E) is one step colder than the stock '6' heat range (BKR6E) and helps prevent detonation under high boost.
Known Issues, Recalls, or TSBs
There are no recalls or Technical Service Bulletins (TSBs) issued by the NHTSA for spark plugs on the 1985-1995 Toyota MR2. Any issues are typically related to normal wear, incorrect installation, or using the wrong type of plug for the application.
Frequently Asked Questions (FAQ)
Do I need to gap new spark plugs?
Yes, you should always check the gap with a feeler gauge before installation, even if the box says they are 'pre-gapped'. The correct gap is important for a strong spark. For most MR2 applications, the gap is between 0.028" and 0.044", but you should verify the specific requirement for your engine and plug type.
Is it hard to change the spark plugs on an MR2?
It is a manageable DIY job for most owners. On the AW11, access is relatively open. On the SW20, especially the turbo model, you may need to remove some intercooler piping to get access, and a socket extension with a universal joint can be very helpful for the plug closest to the throttle body. The job typically takes 1-2 hours.
Why are NGK and Denso so highly recommended?
NGK and Denso are Japanese manufacturers that have supplied parts to Toyota for decades. Their plugs are engineered to work well with the ignition systems in Japanese cars, leading to better reliability and performance compared to brands designed for American or European cars.
What is a 'colder' spark plug?
A 'colder' plug is designed to transfer heat away from its firing tip more quickly. This is necessary in high-performance or turbocharged engines that generate more heat in the combustion chamber. Using a colder plug helps prevent pre-ignition (detonation), which can severely damage an engine.
Helpful Videos
Technical Specifications
OEM Part Numbers: 90919-01164 90919-01178 90919-01180 90919-01121 90919-01127
Engine-specific. Common types include NGK BKR6E/BKR7E for 3S-GTE engines and NGK BCPR6ES for 4A-GE engines. Socket size is typically 16mm (5/8"). Torque spec for aluminum heads is approximately 13-18 lb-ft (18-25 Nm).
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
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