Group Captain Smudger

UK MY97 Turbo, 60,000miles: P1 (STi) backbox; K&N induction kit

Symptoms: when hoofing it it has a tendency to hesitate quite badly at times (similar to fuel starvation). If I'm brutal with the accelerator the car shudders quite violently, which the kids in the back find amusing but of course I don't. Now I can almost sense when this is about to happen. Gentle pressure on the accelerator alleviates the problem.

Thought it could be the plugs so these were recently replaced with new PFR6Bs. Old ones were mucky brown and the gaps were on the large side but the problem is still there. The only other symptom of note is that the backbox has a sooty rim. Others on this db have mentioned that MAF sensor failure can be indicated by erratic tickover. I wouldn't say mine's erratic but I've noticed on several occasions the revs dying and then picking up again (mainly on slow downhills when the engine is cold). Normal tickover (when warm) is about 750rpm.

Any help/advice appreciated.

Graz

I'm sure someone will be along soon with much more technical expertise than myself but does the MY97 not have the hot wire type MAF which is much less prone to failure than the film type fitted to the more recent models?

The erratic tickover normally follows an ECU reset so that may be worth trying (leave battery disconnected overnight). I think you can also unplug the MAF with the engine running. If it stalls then the MAF is probably okay, if the revs stay the same then it may be knackered.

DEKA

Have you done a diagnostic check? to see if there are any fault codes
Sooty rim on the back box. Hmmm might be a goosed O2 sensor

misty

Someone hasn't swapped your engine for a diesel overnight have they mate????
dave