Diagnostic Aids
WARNING: This page is about a different car, the 2003 GMC Sierra and 2003 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Excessive vibration from sources other than the engine could cause DTC P0300 to set. The following are possible sources of vibration:
- Variable thickness brake rotors.
- Drive shaft not balanced.
- Worn or damaged accessory drive belt.
- There may be more or less cylinders actually misfiring than indicated by the scan tool.
- Spray water on the secondary ignition components using a spray bottle. Look and listen for arcing or misfiring.