Operation CHARM: Car repair manuals for everyone.

Light Knock Hot

- Detonation or spark knock. Check operation of Electronic Spark Timing (EST) or Electronic Spark Control (ESC). Check engine timing and fuel quality.
- Loose torque converter bolts.
- Exhaust leak at manifold. Tighten bolts and/or replace manifold.
- Excessive rod bearing clearance. Replace bearings as necessary.