I have a 2003 WRX with some minor prodrive mods. The car has 125K and I took it tracking for the first time a few weeks back. After a few sessions at track, my third cylinder was misfiring, to the point where my check engine light came on. My car had a very subtle symptom of this for about 6 months prior to track but I thought it was a slipping clutch. The symptom originally only appeared in 5th gear under high load, but at track, it got to the point where it would slip (backfire) in every gear. When we hooked a OBDII reader up at track, it stated 3rd cylinder misfiring. A friend helped me switch out the spark plugs and the car wouldn't misfire but my engine has begun to whine. Kinda like teh sound a dog would make when its lonely. It sounds like its coming from the alternator but im not sure. I also noticed that in first and second gear, when i accelerate at a constant rate, i see that my boost goes up and drops without taking my foot off the accelerator...I dont remeber it always doing this...
I have a track day at Laguna in abot 6 weeks and I need to get my car ready for it. Does anyone know what the whining is and if it could be related to the turbo.. Should i have someone dyno the car to see if its a flaky turbo/
Any and all help would be greatly appreciated. THanks guys.