Hi Guys, This is a hard one to explain so bare with me...
Car is pretty standard apart from a STI Genome exhaust and a boost gauge, has done less than 100,000km and is in pretty good nick. It runs and boosts well, sounds like it should with no knocks or other suspect noises. I\'ve had the car for about 9 months now and it has just started to stutter when under load in 3rd, 4th, and 5th gear at around 3500-5000rpm. The stutter is hard to explain, the revs spike up and then drop down and then build again without changing throttle position (not always at WOT). It seems to be intermittent but has never happened in 1st or 2nd gear, The easiest way to get it to stutter seems to be to sit at a constant 50kmh in 4th gear and to open throttle from there without changing down (If I do a standing start and push it hard through all the gears it doesn\'t seem to do it). At first I thought it might have been clutch slip but it wont do it from a standstill when you push it hard and I have tried a steep hill start in 4th gear with plenty of revs and it stalled and wouldn\'t slip. It seems like it could be boost or vacuum related but I cant see any loose or perished hoses?
I\'ve been told by a mechanic that it\'s not a mechanical problem, and most likely a faulty sensor or some other electronic related problems. I haven\'t had a OBDII tool plugged in yet to see if it\'s throwing any fault codes, But that\'s my next step. I\'m waiting for it to arrive :-[
Any ideas?