Hey I've posted on here about this issue a few times I think. I finally took my truck to the shop I use when I can't figure stuff out a few months ago for a p0171 174 code. They smoke tested it after I threw a few parts at it and did a propane test on the manifold and I fixed a few hvac lines for the vents and they said my fuel trims were high due to a maf sensor and it had good fuel pressure and no leaks so they replaced it and all has been well it even quieted the motor down where it sounded like it ticked st idle. Today the codes came back about 1200 miles since they fixed it with a new maf. Any ideas?

 

Was the MAF a cheap aftermarket one?

 

It's not a motorcraft it's whoever their supplier was all i know is it's new. Are these trucks picky on aftermarket junk? I cleaned the old one and I figured it was good but still had high fuel trims they diagnosed it and replaced it and now it threw the same code as I said. Should I get ahold of a live data scanner and see what maf readings are? Any idea what it should read?

 

It's poboably because it's not a Motorcraft MAF. Yes, Fords are fussy . I would just take it back to them because a MAF should last longer than 1200 miles.

 

Unless you are using an oiled air filter such as a K&N.

 

I appreciate your reply. I'm going to borrow a live data scanner and research what the maf is and what should be and if it's out of whack go visit the shop who put it in and pull a Karen on them

 

I had a non-Motorcraft MAF once and it checked out fine for voltages but still gave me lean codes because it wasn't producing the right barometric pressure readings. Indicated I was at 6000 ft elevation but I am closer to sea level. Make sure to check the baro readings.

 

Yes, that would be like begging for problems.

 

Could be as simple as a vacuum line they didn't fix before. When I do work on a vehicle that old, I replace each and every one of them. They can look fine and still be dry rotted and allow air in