In responce to antgtir issue regarding "Hesitation between 3k to 4.5k rpm + Fueling issues??" I had a similar problem.
I picked up a GTIR last month and felt it was running a bit funky. It seemed to pick up ok at low revs but stuttered and hesitated badly between 4.5 - 5k rpm. When I layed off the gas the damned thing wanted to go. Not good when you are entering a corner looking for engine breaking. It was also idling high (1100rpm) and just felt a bit unwell.
The car it's self is bulk standard except for a mongoose exhaust (without cat) and sump guard but with a poor service history (jap 18k service). I bought it off a farmer who had owned it for 4 years and done 2k miles in that time. It has 60k on the clock, it was imported in 2002.
Anyway, given the service history and poor performance, I booked it in for the full boona.
Falkland performace changed all the fluids, plugs, point, air filter (now K&N) front disks and pads and rear pads. (disks and pads were well shot.... it was grinding along)
I was full of hope but the car was still running poorly.
It turned out to be the knock sensor (error code 34) This sensor they explained was there to pick up pinking etc and when triggered would retard the ignition timming by 6deg. It's meant to reset it's self but did not and I thing I will source a new sensor.
They reset the ECU and the error was gone. The car is now running fine. Much smoother, pulls all the way through the rev band and thankfully enters engine breaking now when I gas off. I did refrain from taking it out on the track at knock hill last sunday however as I have a sneaky suspition the problem would return plus I did not want to buy another set of brake pads so soon.
Hope this information helps and I may post it in a couple of other places on this web site.
Lang may your lumb reek... all the best Braveheart (Scott)
