Hi!
P0171 come on - 2000 Toyota 4Runner 39,000 miles

1) Change the air filter
2) Change fuel filter
3) Clean MAF sensor
4) Clean air system (infusion)
5) BG K44 to fuel tank

60 miles P0171 again...
Any ideas? May be replace MAF sensor to new one?

 

Did you clear the code after the repair?

 

Yes )))

 

cleaning will only help sometimes. Sometimes the maf is just bad.

 

Yeah I'm with ya!

My CEL has been on and off for the last 40,000 miles and it's the P0171 the whole time! In addition to what you've listed, I also sealed up some small vacuum leaks in my intake system with FIPG (downstream of the MAF). And the CEL came on again!

I've tested the MAF voltage and impedance and it seems to be within FSM specs. Should I try replacing it anyway???

The good news in all this is that the truck runs like new, and still gets reasonable MPG at 17-19 on most fill ups. So I'm a little hesitant to put any money into the problem.

 

I got P0171 too. I cleaned maf and didn't help so I bought new maf. Problem solved. It helped idle smoother. I've gotten no P0171 code for 3 years now.

 

You might also want to change where you buy fuel if you can't get the P0171 to clear.
I work at Lexus and we had a bunch of cars come it with this issue. Turns out that a fuel tanker dropped off the wrong fuel at several gas stations. It was on the news. We think it was E85 but can't be sure.

 

Same exactly problem - MAF sensor voltage is correct and i cleaned MAF sensor and my 2000 4runner has only 40,000 miles (needle in hay stack) And its not good acceleration (i had Pathfinder 2002 he was jumping ahead like crazy any time i pushed pedal) and 4Runner start like old horse
Toyota dealer's mechanic any ideas? Change the MAF anyway ?
I fuel the 91 only at the same station all the time (KingSoopers reward gasstation)