Hatter

I have got a 97 STI3 Vltd, with HKS induction kit, Scoobysport exhaust, and unknown dumpvalve, otherwise standard. Its always run on Optimax and Millers, but recently when cold, I can feel the car "hesitating" almost as if it's running on 3 cylinders, it's worse if pulling away from a rolling start in 2nd gear. Also the car occasionally "Kangaroos" whilst pulling away in first (not clutch judder).

I have had the car recently serviced by a main dealer, they have checked for fault codes but didn't find any, and surprise , surprise on a test drive it behaved perfectly. Anyone got any bright ideas? your help would be much appreciated

scoobyslut

sounds like a bit of overboosting or maybe the knock sensor might be picking something up and retarding the ignition.
Perhaps a quicky would be to relocate the knock sensor from its original position and set back onto the bracket which holds the engine earth lead. it s then a bit more "remote" maybe then, not so sensitive, but a cheap option to start with.