Hi all, im just after some help with my S3. Its a pretty long story tbh so i wont go into it. Basically at when i put my foot down i get to about 4000rpms and it starts misfiring really bad.. Im not sure if its a boost problem on something else.
I have had new
Coil packs
N75 valve
Lambda sensor
Air maf
Map sensor
Vac pipes
TIP
i have also had it put on vagcom and nothing comes up when scanned.. The thing i wanted to ask you guys is, when i was playing round with it the other day i took the vac pipe off the top of the dump valve and didnt put it back on. then when i ran it down the road and the car ran fine just with less boost. I then put the vac pipe back on and the problem came back. so after a bit more playing i noticed that on tick over and light revs that top vac pipe sucks which i guess is normal, but if i rev it hard then that same vac pipe stops sucking and starts blowing.. so effectively im guessing that when driving the car with my foot down that top vac pipe must be blowing down on the piston.. now im not a mechanic and im not that great with engines.. can anyone please tell me A, if this is ment to happen or not? And if its not ment to do that then has anyone got any ideas as to what could be causing it and how i fix it??
i thank you all for reading and any help you can give me. This problem has been gettin me down for months now and i seem to spend all my time and money working on the s3 and not getting it fixed.. i have been to mechanics at several different garages and they all say something different.. then a guy on Facebook said that there are some very knowledgeable people on here so i thought i put a post up and see if anyone can help..
Thank you for reading
Dave
I have had new
Coil packs
N75 valve
Lambda sensor
Air maf
Map sensor
Vac pipes
TIP
i have also had it put on vagcom and nothing comes up when scanned.. The thing i wanted to ask you guys is, when i was playing round with it the other day i took the vac pipe off the top of the dump valve and didnt put it back on. then when i ran it down the road and the car ran fine just with less boost. I then put the vac pipe back on and the problem came back. so after a bit more playing i noticed that on tick over and light revs that top vac pipe sucks which i guess is normal, but if i rev it hard then that same vac pipe stops sucking and starts blowing.. so effectively im guessing that when driving the car with my foot down that top vac pipe must be blowing down on the piston.. now im not a mechanic and im not that great with engines.. can anyone please tell me A, if this is ment to happen or not? And if its not ment to do that then has anyone got any ideas as to what could be causing it and how i fix it??
i thank you all for reading and any help you can give me. This problem has been gettin me down for months now and i seem to spend all my time and money working on the s3 and not getting it fixed.. i have been to mechanics at several different garages and they all say something different.. then a guy on Facebook said that there are some very knowledgeable people on here so i thought i put a post up and see if anyone can help..
Thank you for reading
Dave