I have a my00 with a full decat and blitz induction kit, over the past few months ive noticed a judder when the turbo is starting to kick in and revs are kept constant. It feels as if the car wants to go but is being held back. Ive also noticed that the car sometimes hunts on idle and stalls. Does anybody know what the problem is?

 

The hunting on idle could be your MAF sensor failing (not good btw), this could (and probably is) due to your induction kit as MY99/00 MAF sensors are extremely sensitive to change.
The turbo judder could be (and sounds like) mild overboosting, this is where you hit the upper limit on your ecu for boost (the ecu then corrects this by cutting power), cause.... full decat and your induction kit.

Tony

 

hi mate i used to have the same problem on my 97 wrx the best way i could describe it was when i used to put my foot down the power used to come in surges and it used to hunt on idle, also was a bit thirsty on the optimax. i changed my lambda senser and it cured everything. a goood smooth power delivery no hunting etc. i got my universal lambda senser from www.cats-direct.com. peeps did say it was the maf but go for this first it'l cure it and its cheaper