Ok I posted a short while ago about the mysterious misfire in cylinder 3 of my 1998 E250 with 4.2L. At that time I changed the fuel filter and unplugged the battery for hours and the problem finally went away.

It went away till this week at least. Same issue check engine comes on, Misfire cylinder 3. I erased the code twice with my codescanner only to have it come back a short time later.

Heres the kicker - I decided to unplug the battery two days ago to try it out and guess what, 150 miles and no check engine light. Does this point to a computer issue? Ideas? I linked my original post below.

https://www.fordforum.com/forum/ford...374/#post90269

 

Anytime you clear the CEL/DTC's the lamp will usually stay out until the diagnostic monitors complete/drive cycles are met. They will eventually be completed under normal driving conditions but may take some time and mileage. They can be forced with specific driving strategies.

As mentioned before with the misfire, if the comps spec. out, all ignition related possibilities seem to be covered, and the misfire is more random or predictable (should rule out base engine issues) then at a no/low cost check, you may want to move the injector to another cylinder and see if the misfire moves with the change. Or, just try a new one in that hole. But with 200k, the possibilities do widen a tad..

 

I was afraid I'd have to mess with the injector. In my explorer it wasn't a big deal everything was on top. In the E250 its just a PITA trying to get everything out. Thanks for the input looks like I'll replace at least that injector.