Me again!
Had my 2004 GTP CompG for a couple weeks now and have been working on tuning it up and trying to fix a misfire at idle.
At first it was sort of mild, but still bad enough to occasionally set off codes if idling for too long (for a bit it was Cyl 4 misfire, otherwise it was always Random/Multi misfire, codes P0302 and P0300 I think)
Since I've been working on it, it has improved a ton, but it's still there. Can't much feel it in the floor anymore, but you can hear it in the exhaust and when watching the engine.
It only happens at idle, and it disappears temporarily (few minutes) if the engine is revved a little or even after a brief drive up the street.
What's been done:
- Oil and filter
- Fuel filter
- Spark plugs & wires
- Thorough TB cleaning
- Air filter
- Seafoam (gas tank only)
The biggest difference was noticed after the first seafoam use on full tank, then I noticed a little bit more of an improvement after changing plugs and wires.
I've noticed that after the car runs for a bit the injector on Cyl 3 has, what appears to be, gasoline collected around the top of where the injector sits. So because the first seafoam showed a difference, and an injector is wet, I decided to do another seafoam on an emptier tank to try and clean the injectors, but it's still there.
Misc info:
- Oil, trans fluid, coolant, SC oil, have all stayed at proper levels since I've had the vehicle
- "Hot engine" smell after any normal trips. Don't know how to describe this smell other than just it smells like under the hood of a typical warm running engine. Doesn't smell like anything burning.
I wonder if this could just be light leftover oil from when the valve cover used to leak (fixed).
- 91 Octane only
- 65,000miles/108,000km
- runs pretty steady at 85c/185f coolant temp
- coils don't arc when wet (i.e. no cracks)
- old plugs looked healthy when removed
- OBD2 reads KR staying at 0.0 at almost all times, except climbing up to 3-4 when going up hills in 4th, and sometimes briefly jumps up to around 3 when accelerating at about 3,000 RPM
Sorry for the book, still new and learning. Any help is appreciated
