First timer, here. I know everything I know about my car through this site so thanks!
I've got a 2001 Jetta Wolfsburg 1.8T with just under 104K miles. It's running fine but I've been chasing down this P0170 code for a few months and now my inspection's due so the pressure's on to get it fixed (as if it wasn't before).
The car runs fine with the exception of cold starts. I've scoured the forums and hope I haven't missed anything obvious, but here's what I've done so far:
-replaced MAF (just tested this under load at redline and got readings of ~156 g/s. My car has an APR chip so I assume these readings are good. I aslo assume this rules out the MAF as the culprit.
-checked for obvious vacuum leaks to no avail
-replaced pre-cat O2 sensor (was originally throwing P0133 so it wasn't just on a whim)
I'm still inclined to suspect a vacuum leak and need to do replace the braided lines anyway but it must be a small one. So my questions:
1. Would VAG-COM give me more info than my OBDII scanner about fuel trim specifically and narrow down the possible issues (ie, determine whether it's a vacuum leak or a sensor failure)?
2. Since I reset my CEL, all monitors have come back up except the catalytic converter monitor. That one still comes back incomplete. Is it possible the post-cat O2 sensor is involved with that? I know it's not directly involved with fuel trim issues like the pre-cat sensor.
3. Do any VAG-COM owners in Austin (78704) feel like helping out?