[s-cars] rough idle

[Martin Baggenstos]

Hello everyone,

  Hopefully someone will be able to diagnose what is going on with the idle
on my car which is a 1995 S6 sedan with RS2 mods and MRC software.. Whenever
the car is at idle, according to my air fuel meter, the car runs very lean
and if I turn the AC off it runs leaner and the cars idle is rough. In
both situations, the check engine light will come on after about 10 seconds
but will go away if I press on the gas. I have checked my ignition system
and it is fine. The only recent changes with the car are that I put a high
flow in-tank fuel pump from 034 motorsports in the car. I also have the high
flow delphi injections which go with my MRC software but even though the
pump is high flow, it should not affect the fuel delivery from the injectors
because they will only deliver what the software tells them to, correct.
Also could this be something to do with my oxygen sensor, which I have not
changed in a while. My idle control valve was replaced 1 year ago, but could
it be a problem with that now. I do not seem to have any other problems with
driving or boost besides at idle. I have also run vag-com diagnostics
without any warnings or codes. Any thoughts? Thanks.

Martin