A Guide to Selecting Spark Plugs for Your 1983-1992 Isuzu Impulse
Keep your classic Impulse's unique engine running strong by choosing the right spark plugs for your specific model.
- Always use NGK or Denso brand spark plugs for the best reliability and performance in your Impulse; they are the original equipment suppliers.
- You must verify the correct part number for your specific engine, as SOHC, DOHC, and Turbo models require different plugs.
- For turbocharged engines, upgrading to Iridium plugs from NGK or Denso is highly recommended for durability and consistent performance.
- Always check and adjust the spark plug gap before installation, even if the plugs are advertised as 'pre-gapped'.
Signs of Failing Spark Plugs
Worn-out spark plugs can cause noticeable problems with your Impulse's performance. Because these symptoms can also point to other ignition issues, it's important to know what to look for. If you experience one or more of these signs, it may be time for a new set of plugs.
- Rough Idle: Your engine may shake or vibrate when the car is stopped.
- Engine Misfires: You might feel a stutter or hesitation from the engine while driving, sometimes accompanied by a popping sound from the exhaust.
- Trouble Starting: The engine may take longer than usual to turn over, especially in cold weather.
- Poor Acceleration: The car may feel sluggish or slow to respond when you press the gas pedal.
- Reduced Fuel Economy: Inefficient combustion from bad plugs forces your engine to use more fuel.
- Check Engine Light: A misfire will often trigger the check engine light, with codes like P0300 (random misfire) or P0301-P0304 (for specific cylinders).
Engine Differences Are Critical
The 1983-1992 Isuzu Impulse used several different engines. The first generation (1983-1989) had SOHC engines, including a turbo model. The second generation (1990-1992) used DOHC engines, also with a turbo option. These engines require different spark plugs with specific heat ranges. Using the wrong plug can lead to poor performance or even engine damage, especially in turbocharged models. Always verify the correct part number for your exact year, model, and engine type.
Choosing the Right Aftermarket Spark Plug
For a classic Japanese vehicle like the Impulse, aftermarket spark plugs from original equipment (OE) suppliers offer the best combination of quality and value. Here’s a breakdown of the available brands to help you choose.
Tier 1: OEM-Quality Brands
These brands were often the factory-installed choice for Isuzu and other Japanese automakers. You can't go wrong with them for stock or lightly modified engines.
- NGK: Widely considered the gold standard for Japanese vehicles. NGK plugs are known for their reliability, longevity, and consistent performance. They offer standard copper (V-Power), platinum, and iridium (Iridium IX) options that are excellent choices for any Impulse engine.
- Denso: Another top-tier Japanese brand and a direct competitor to NGK. Denso is known for its innovative designs, like the U-Groove ground electrode, which improves ignitability. Their iridium plugs are highly regarded and provide a powerful, stable spark.
Tier 2: Reputable Aftermarket Brands
These brands are well-known and produce quality parts, though they may not have the same specific engineering for Japanese engines as NGK or Denso.
- Bosch: A major German parts manufacturer that produces high-quality plugs, including long-lasting double iridium models. However, some owners of older Japanese cars report issues with certain Bosch platinum plugs fouling prematurely. One retailer specifically advises against using Bosch Platinum+4 plugs in turbo engines.
- Champion: A long-standing American brand that offers reliable performance at a good price. Their copper and iridium plugs are a solid choice for daily driving.
Copper, Platinum, or Iridium?
Copper plugs (like NGK V-Power) are the most affordable and offer excellent performance, but they have the shortest lifespan (typically 20-30k miles). Platinum and Iridium plugs cost more but last much longer (60k-100k+ miles) and provide a more consistent spark over their life. For a turbo Impulse, an iridium plug is a worthwhile upgrade for its durability and performance under high heat and pressure.
Tier 3: Economy & Specialty Brands
These brands can get the job done on a budget or serve a specific performance niche.
- Autolite: A common budget-friendly brand that meets basic requirements.
- Skyward: An economy brand that offers a low-cost replacement option. No specific performance reviews are available.
- MSD: A performance-focused brand. Their plugs are designed for highly modified or racing engines and are generally not necessary for a stock Impulse.
Aftermarket Spark Plug Cost for 1983-1992 Isuzu Impulse
| Plug Type / Brand Tier | Price Range (Per Plug) | Typical Lifespan |
|---|---|---|
| Economy (Autolite, Skyward) | $3.35 - $7.00 | ~20,000 miles |
| Standard Copper (NGK, Denso) | $3.50 - $8.00 | 20,000 - 30,000 miles |
| Platinum (Bosch, NGK, Denso) | $5.50 - $12.00 | ~60,000 miles |
| Iridium (NGK, Denso, Bosch) | $10.00 - $21.65 | 80,000 - 100,000+ miles |
Frequently Asked Questions
How often should I change the spark plugs on my Impulse?
It depends on the type of plug. Standard copper plugs should be changed every 20,000 to 30,000 miles. Platinum or iridium plugs can last much longer, often from 60,000 to over 100,000 miles. Given the age of the vehicle, inspecting them every 30,000 miles is a good practice regardless of type.
Do I need to gap the new spark plugs?
Yes, you should always check the gap. While many plugs come "pre-gapped," they can be knocked out of spec during shipping. Use a feeler gauge to verify the gap matches the specification for your Impulse's engine and adjust it carefully if needed. An incorrect gap can cause misfires and poor performance.
Is an expensive iridium spark plug worth it for my Impulse?
For a naturally aspirated, stock engine, a standard NGK or Denso copper plug provides excellent performance for the price. For a turbocharged Impulse (4ZC1-T or 4XE1-T), an iridium plug is highly recommended. It offers better durability under the higher cylinder pressures and temperatures of a turbo engine, providing a more stable spark and longer life.
Are there any recalls or TSBs for Impulse spark plugs?
No, there are no known recalls or Technical Service Bulletins (TSBs) from Isuzu or the NHTSA specifically concerning spark plugs for the 1983-1992 Impulse.
Technical Specifications
OEM Part Numbers: 8943283720 8943283740
The Isuzu Impulse was equipped with a range of 4-cylinder engines from 1983 to 1992, including 1.9L/2.0L/2.3L SOHC engines and 1.6L/1.8L DOHC engines, with both naturally aspirated and turbocharged versions available. Each engine requires a spark plug with a specific thread size, reach, and heat range. Common aftermarket part numbers for the DOHC engines include NGK BKR6E (V-Power), BKR6EGP (Platinum), and BKR6EIX (Iridium). Always confirm the correct part for your specific engine before purchasing.
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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.
- Isuzu Impulse:
- 🛍️ Shop This Part
- Signs of Failing Spark Plugs
- Engine Differences Are Critical
- Choosing the Right Aftermarket Spark Plug
- Tier 1: OEM-Quality Brands
- Tier 2: Reputable Aftermarket Brands
- Copper, Platinum, or Iridium?
- Tier 3: Economy & Specialty Brands
- Aftermarket Spark Plug Cost for 1983-1992 Isuzu Impulse
- Frequently Asked Questions
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