Rough, Unstable Idle
- Check throttle linkage for sticking. Check idle speed. Check IAC system. See Idle Air Control Test chart. Check alternator output voltage. Repair if less than 9 volts or more than 16 volts.
- Check injector balance. See Injector Balance Check chart. On all 3.8L V6 engines, check EGR. There should be no EGR at idle.
- On both engines, inspect O2 sensor for silicon contamination from fuel or improper use of RTV sealant. Sensor is defective if it is coated with a white, powdery coating.