P0171 Lean Code Diagnosis

[MetalMan]

Luckily headlight removal is only a few screws!
Speaking of screws, the ones with speed nuts you sent showed up yesterday. That was fast!

[fR3ZNO]

Edit: And while you are sucking all that unmetered air you will get a lower than expected MAF g/s which is what causes the high LTFT. (also sounds familiar).

Just to play devil's advocate here; if the MAF itself was faulty and was giving a lower than actual air flow reading, wouldn't the LTFT be high as well, since the ECU is thinking its getting more air than it's expecting?

Luckily headlight removal is only a few screws!
Speaking of screws, the ones with speed nuts you sent showed up yesterday. That was fast!

Yep! I'm glad headlight removal doesn't require taking the bumper off too.

That's priority mail for you I won't tell anyone you have Passat screws in your S4

[old guy]

Just to play devil's advocate here; if the MAF itself was faulty and was giving a lower than actual air flow reading, wouldn't the LTFT be high as well, since the ECU is thinking its getting more air then it is expecting.

Easy enough to check. Unplug the MAF and take it for a spin. If the problem is the MAF sensor you should see a significant drop in your long-term fuel trims.