mrmnico

Have an '06 a4 1.8T Cabrio. Been getting p0171 p0507 for near a month. Spent $$$$ at the dealer and another $$$$ at a private repair shop with no result. Can't seem to clear the codes and can't pass the Emissions test. Replaced pcv, various hoses & clamps, coils, and plugs. Ran injector cleaner through once tankful of gas. Engine runs strong as new. But still getting the two codes.

ltooz_a6_a8_q7

What are those codes ?
Did you check the MAF?

mrmnico

I didn't take it apart I just monitored it while Driving and all Values. At Idle I am getting around 2.8 to 3 g/s and driving there are no issues. Turbo spools up and it drives as expected. So here is the scenario. I reset Computer. Car runs like crap. Like my coils and plugs are bad (its been changed already). I monitor what the engine is doing ( I have a bluetooth OBDII reader) P0171 Pops up but no check engine light yet. The engine finally settles and starts to run normal (no more stuttering or spurting) Check Engine Light comes on again. Thus Failed Emissions Yet Again.