Incredible Mileage! But it's a problem.

[adkinsadam1]

Today I was driving back on a long road trip, and my check engine light came on shortly after getting gas. I was able to diagnose the code as PO171. I had the light turned off and continued home and the light did not come back on, but I noticed a distinct lack of power. Power was just so much less that going up mountain hills and passing anybody was basically impossible. It seemed like noticeable drops in power would occur as the RPMs increased past 3000. In addition, this last tank of fuel is apparently showing incredible mileage! I drove 270 miles and my fuel is still at a half tank! This mileage and the loss of power and the PO171 must be connected.

Is there anybody with experience with this? What is the best course of action?

 

[JEL]

I'd probably hand calculate that to be sure something weird isn't going on with that fuel gauge, they are known to be horribly inaccurate. In any case, I had that code April 2013 and all it took was a good cleaning on the MAF, never came back. I suppose you could be running extremely lean if the MAF is in fact the culprit, but I didn't have my CEL on long enough to measure the mileage as I cleaned the MAF pretty much right away.

 

[adkinsadam1]

My fuel gauge has actually been very accurate up until this tank. It would be strange to me that it suddenly changed... But the main thing that I don't like is the significant loss in power, and inconsistency of power as I accelerate. Does it sound like an actual engine problem or a sensor issue?

 

[JohnMc]

Sounds like a MAF issue to me. The lean burn is good for MPG, but not for power or longevity of the engine (higher combustion temps).

Clean the MAF to see if that improves the situation, if not, replace it.

 

[Atrox Caeda]

Yea, you definitely don't want to be running lean for too long... melting engine parts is bad.