S4 T2 sound like misfire?
 

No emissions stuff at all (thermowax, ect), have BAC with no water lines, S5 keg and S4 electronics zeroed out SAFC on oem S4 T2 ecu (oem maps), TPS is perfect @ .99, AIT sensor is broke. No vacuum leaks and everything seems to be very solid...



I am hearing what sounds like a straight misfire all the way up to around 2k rpm. Like a constant misfire or a studder. Its much worse from 1k up. The car cold starts and idles for about 20 secs perfect then starts doing this.

Totally lost on this one. Maybe AIT? Also i dont think O2 would have anything to do with this. Whats the 2 wire sensor on the very back of the uim? I heard idle something?


Also another problem... car idles up when you put it in reverse???

No help? Anyone?

Try replacing the AIT.

Not sure if the AIT will cause this though..

If you know it is broke,fix it.Maybe it does help,maybe not,but you need the AIT to help the ECU figure out fuel.
another thing is IF you are Premixing,How MUCH are you putting in?,it could cause a fouling of the plugs that clean up after it gets to higher revs.
Ask me how?..I just went through a weekend of tuning with Fouled plugs being a Beotch..took 3 days to get the car running right.