Knock At Idle, Engine Warm

- Detonation or spark knock. Check operation of ignition controls or knock sensor circuit.
- Loose torque converter bolts.
- Exhaust leak at manifold. Tighten the exhaust manifold bolts and/or replace the gasket.
- Excessive connecting rod bearing clearance. Replace bearings as necessary.
- Excessive piston pin clearance.
- Excessive crankshaft thrust bearing clearance.
- Bent connecting rod.