So I finally have my turbo swap going but I cant seem to get it to idle right. First I checked for vacume leaks and found 2 and fixed them. Then I adjusted the TPS as it was off a bit and that made it a tad bit better but not enough. It doesnt die out anymore but it surges between 500-1100 rpm. What I have on it is a JDM Redom chipped N374 ECU, JDM downpipe (no pre cats) , main cat eliminated, Removed some emissions but kept the BAC and thermal wax, also has a lightweight flywheel and 4 puck clutch (came w/ the transmission and I cant stand that clutch in traffic ha ha). Oh and this is a S5 engine. Other symptoms are that when you push the clutch enough to release the top switch on it the idle raises to 1500 and surges there too and it is still lean. Under throttle it is not lean at all but at idle it is. Any help is extremely appreciated!

 

I'd still suspect the TPS is bad. It's possible to have one that will adjust to 1 volt at idle, but still not fully function through the RPMs (I have 2 bad ones that do this). I myself just fixed a surging problem with a new TPS, and it's cheap to swap it out for a used one.

 

Is my s5 na tps the same one? I could swap them if so. Oh and would this fix the lean problem too?

 

Another question is can i test the TPS? Could the alternator be the cause I have been told its a possibility.

 

I need help... and I have some newly exposed symptoms to add. On start up occasionally a gauge wont work... earlier it was the fuel gauge the next time it was the tachometer. The gauges to come back after a few min of running. This is leading me to believe I have bad solders in the computer but could this also be the cause of the surging idle? I am going to do an alternator test tomorrow just because I have the equipment and see if that tells me anything but I am completely lost on this problem.