Intermittent Engine power loss

[Mark in Indiana]

I have a 1991 Explorer XLT (v-6) that suffers from an occasional power loss starting at about 2200-3000 RPM.

Checked and cleaned the Mass air sensor (electric grid thing in the air intake)

Tried a couple cans of Seafoam in the tank and within a couple of minutes it seemed cured. Went about a week, same thing / same cure. Went about two days same thing, not cured... mechanic said fuel pump..... drained fuel, new pump, new fuel, new filter in-tank and in-line... ran great for a day and now back to square one.

Could this be some kind of electrical problem and not throw a code?

What to do???

Thanks, Mark in NE INdiana

 

[marragtop]

Try pulling the codes. It can throw a code, and not turn on the CEL. Also, have you tried cleaning or replacing the IAC?

 

[MarksSC94]

There are quite a few things that can cause this. I suspect there is a problem with an injector where the injector can not deliver the fuel required to turn above 2200 rpm. You will have to get the book on this, but you can disconnect the harness from the injector rails and ohm out each injector. The book will let you know what the values should be. If you find you have one that is out of tolerance, I recommend you replace all of them and not just one if you find one bad. Another thing you can do is check out the plugs and see if one is looks like it has been running poorly, either it is black from a rich mixture or white from lean. The best price ones I have seen are Accel, but you will have to look around. Other things that can cause this? O2 sensors misreading (rare but happens), plugs, wires, ignition system, fuel regulator. You can check the regulator by putting on a fuel pressure guage. If the pressure is low, then it may need replacing. In reality, I would check out the injectors and the regulator first.