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P0305 OBD2 Code on 1999 Olds Cutlass - Spark and Fuel Issues

Model: 1999 Olds Cutlass Fault Code: P0305 Posted: 2016-10-05 13:53

I replaced the coil pack for cylinder #5, but the check engine light remains on and the engine still runs roughly. The issue persists despite the replacement. I'm looking for help diagnosing whether there's proper spark at cylinder #5 or if fuel injection pulsing is occurring. Also, I've performed compression and vacuum checks—results will be shared if needed. For reference: OBD2 code P0305 on a 1999 Oldsmobile Cutlass.

Related fault codes

P0305

Comments (2)

Anonymous 2016-10-05 14:20

Could you please specify the engine type (e.g., 3.1L V6) and exact model year? Additional details will help pinpoint the issue. Check for spark at cylinder #5 using a spark tester. Verify if fuel injectors are pulsing with a scope or multimeter. Also, confirm compression and vacuum readings—these are key diagnostics for P0305. Reference: https://www.obd-codes.com/p030-5

Anonymous 2016-10-07 15:33

I replaced the spark plug and ignition wire for cylinder #5, which resolved the rough idle and turned off the check engine light. Thanks for the advice!