Engine - MIL ON/DTC's P0301/P0302/P0303/P0304
01 08 04January 23, 2008
2017063
Affected Vehicles
Condition
MIL ON, Misfire DTC P0301, P0302, P0303 or P0304 Stored in ECM fault Memory after Cold Start
At times engine may run slightly rough for a few seconds after cold start. MIL may illuminate with a DTC for misfire on one cylinder only (P0301, P0302, P0303, P0304) stored in the ECM fault memory. Rough running condition disappears a few seconds after cold start and DOES NOT exist with a warm engine.
Technical Background
Not applicable.
Production Solution
Not applicable.
Service
1. Follow normal Guided Fault Finding Diagnosis, for example:
^ Swap spark plugs and ignition coils between affected cylinder(s) and good cylinder(s).
^ Check compression and leak-down of affected cylinder(s).
^ Verify fuel quality. (Also refer to Technical Bulletin 2014815 - Gasoline Quality.)
^ Swap fuel injectors between affected cylinder(s) and good cylinder(s).
Note:
When swapping fuel injectors, always replace all fuel injector seals.
2. If diagnosis results are inconclusive, and above mentioned condition persists, replace all 8 Hydraulic lash adjuster (lifters) of affected exhaust side.
Warranty
Information Only.
Required Parts and Tools
For Part No. reference, see table above.
Additional Information
All part and service references provided in this Technical Bulletin are subject to change and/or removal. Always check with your Parts Dept. and Repair Manuals for the latest information.