1998 Ford Explorer MASS AIR FLOW SENSOR

JBONAVISO

MEMBER
1998 FORD EXPLORER
6 CYL
AWD
AUTOMATIC
125,000 MILES

I have a 98 Ford Explorer, I just had a new Tansmission installed, New upper and lower Ball Joints and Control Arms, full Tune up, new plus, etc. My check engine like is on with code P1131 showing. I have the new O2 sensor, But when im idle or if I tap the gas the car stalls. Could this be the MAFS causing the problems, the rpm go between 800 to 1000.

1 Reply

MERLIN2021

MECHANIC
17,250 POSTS

P1131, possible causes, Fuel system malfunction(pressure), EGR malfuntion, Air intake or vacuum leak, engine oil level too high, incorrect cam timing, restricted air cleaner, faulty PCV, worn engine parts.
https://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm
Go here and checkout our video.
You can rent the test gauge at Autozone.
You may have a vacuum leak, get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody