92 Explorer 4.0L engine surges.

[jamesapost]

im new to the form and just wanted to share some info. my engine started to pulses, the idel would fluxuat ranging from 800 rpm to 4000 rpm and some times stay at 4000 rpm foe a few seconds and then drop back down to normal! i changed the mass air flow meter, the throtel position sensor, the idell air controler and was getting ready to change the o2 senser. i decided to check the fule presure since i just put a 2nd new fule pump in the first new one from auto zone failed after 500 miles, never get a fule pump from auto zone!!! but the presure was good. i started the truck and let it run foe 30 min, to get to operating temp, and it was running good, took it for a test drive and still good! the problem was the power miror contrloer had shorted out and melted causing power surges in the system of some sort and i removed the short and the truck id good as new! i hope this info helps someone in a simular situation

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the stock 91-94 section.

 

[Splash94]

Oh boy. I had the same problem with my 4.0 94 ranger. i replaced the fpr, the spark plugs, the ignition wires, and finally the maf sensor. the maf was the one to solve the problem. engine ran so much cleaner and smoother after the plugs though. Definately the first thing to check. Just thought i'd add that little bit.

 

[deamon3]

Mine would jump rpms all over the place at times. I thought it was really broken seriously , until I figured out it was just the fan blower made it run funny , when I turned the blower off it ran fine. lol