Somebody please help me. Here's the problem.....drove my truck like 100 miles on friday night, ran perfect no problems. Parked it at home in the drive way, got up the next morning and started it up and it had a miss and ruff idle.(feels just like a bad coil pack) i have the sohc 4.6l win. Motor. When it gets warm my truck goes into limp mode, barly revs up to 3000 rms and will only go like 45mph. Codes wer p1131, p1131. Mass air metering? I have replaced mass air flow sensor, throttle position sensor, and swapped around coil packs and i have checked plug wires, but no code is throwing to tell me why its going into limp mode. Please somebody tell me they have had this happen before. Oh yeah its a 1999 f-150 4x4 by the way. Its driving me insane. OH YEAH, IF YOU TURN THE TRUCK OFF AND CRANK IT BACK IT RUNS FINE UNTIL IT GETS HOT AGAIN.

 

Are you sure it's not actually overheating? Have you checked your coolant level lately?

 

yeah all the fluid levels are full. Will one broke down spark plug cause it to go into limp mode? the miss isn't to horrible, but its enough to drive me crazy. but the only thing close to telling me that is one troubleshooting explanation from the autozone code scan was misfire on bank one.

 

fixed the problem, changed my heater core a week ago and i guess some of the water went into the #4 spark plug hole and caused a misfire. sucked out the water with a shop vac, replaced the plug and wire, now i have my truck back! yay

 

Congratulations! And thanks for letting us know what the problem turned out to be. We all learn that way!