My car was acting up for the last few months - low on power and stumbling on acceleration. Finally, it throw a code last week PO171 - too lean Bank 1.

I tried everything to fix this issue including:
1. Plugs
2. New front O2s
3. Vacume leak test - manifold, MAF
4. PCV leaks
5. Exhaust leak - head and LT collector

...nothing seemed to cure the issues.
Finally, I pulled out the old factory MAF and replaced the SLP 85MM unit I bought about 4 years ago.

Bingo - the car is running great - no stumbling at all - MUCH more power too.

 

Got any scans of the car while the MAF was bad?

Glad you found your problem too, bet it feels good.

 

MAF's = the spawn of Satan.

 

no, uncalibrated MAF's==the spawn of forums' hype populated by mathematically challenged people

 

The SLP unit that was bad was "calibrated" by SLP. WHen I bought the thing they make you fill out a questionaire about the mods you have. The unit came with a resistor type device that is plugged into the cable between the MAF and the PCM.

Anyway, I tuned the car with Edit afterwards and it ran great for a few years. I'm assuming the MAF went south and that it does not have anything to do with the tune.

Is this correct?