2000 Corolla Lean Fuel Trims After Replacing MAF

I replaced the MAF on my 2000 Corolla with a new Denso MAF and now fuel trims are lean (fuel trims were within spec before replacing the MAF). LTFT at idle is pegging at 19.5, sometimes it comes down to 17. STFT at idle varies from 3-12. LTFT comes down quiet a bit to around 11% while driving, where STFT fluctuates -3 to 8%. I checked to make sure the MAF was seated correctly and it does have the o-ring. I am not throwing any trouble codes. I have not re-installed the old MAF, although I will since it’s possible the new MAF is defective – but would that drive the fuel trims that high?

The previous owner of this car threw a lot of parts at it to try to remedy a misfire – one of those parts was a Dorman MAF. I have been having some slight hesitation around 1/3 throttle @ low RPMS. I figured I’d go ahead and replace the cheap part with a factory part and start there.