FaderUS Posted December 15, 2016 Share Posted December 15, 2016 Hi all, I just acquired a 2005 legacy gt 5eat, 160k miles, catless uppipe, Cobb CAI, stock downpipe and unknown brand catback. Stock tune. I have put 500+ miles on it in the last couple of weeks. Initially it had a CEL for the front o2 sensor which I replaced and the light went away. I also had to pull the TMIC and drill out a mounting bolt that was broken on the diverter valve. The wastegate actuator mount was also loose. Per the PO the turbo, banjo bolts, radiator, and head gaskets and timing belt have been done within the last 20k. All was well and the car has been running well following these patches but last night I suddenly got a P0304 misfire on #4. It is a solid CEL, no flickering and can be cleared with a reader but has come back 2 additional times in about 30 miles of driving. Each time the error popped on after the engine was warm, and went from being driven at 55-60 then came to a stoplight. The idle was a little low and rough at the stop light. The CEL popped on as I lightly touched the throttle after the light changed. It does not occur each time I duplicate this process. I have no visible smoke from the oil filler. I have not done any diagnostics other than the smoke test. I had planned to do a compression and leakdown test, plugs, Blackstone oil analysis and oil change as part of the "new to me" assessment. What should my next step be? Swap coil packs? Injectors? Is a Compression/Leakdown test a definitive way to rule out ringland failure? Thanks for any input. -Chris Link to comment Share on other sites More sharing options...
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