Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1994 GMC Forward Control 7.4 NFACTORY OEM SERVICE PROCEDURE
Spark Plugs
SPARK PLUG TYPE
| Application | AC | |
|---|---|---|
| 4.3L | ||
| VIN W | CR43TSM | |
| VIN Z | CR43TSM | |
| 5.0L (VIN H), 5.7L (VIN K) & 7.4L (VIN N) | CR43TS | |
SPARK PLUG SPECIFICATIONS
| Application | Gap In. (mm) | Torque Ft. Lbs. (N.m) | |
|---|---|---|---|
| 4.3L | |||
| VIN W & Z | .045 (1.14) | 11 (15) | |
| 5.0L (VIN H) | .035 (0.89) | 11 (15) | |
| 5.7L (VIN K) | .035 (0.89) | 11 (15) | |
| 7.4L (VIN N) | .035 (0.89) | 11 (15) | |
Factory Service Tools
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.