99 2.5L, rough idol and misfiring during acceleration and driving

[Ave345]

This problem has been around since I bought my Ranger, but it also comes and goes, so I always end up forgetting about it but now it seems like it’s back and is going to stay.

When it first started misfiring, I replaced the MAF sensor, air filter, plugs and plug wires, and it ran perfectly until about a month later when it started happening again, but then it went away again. It went through this cycle a good 3 or 4 times over the course of about 8 months. Check engine light came on and it threw a code for low input to MAF, P0102. I’m thinking it could be the wiring that’s going bad but I also think my MAF sensor could be bad too.

I’m replacing the fuel filter today and I’m probably going to get a new MAF soon, but any other causes to my issue that you can think of, I would appreciate it. Thanks.

 

[tomw]

Are you perchance using a K&N or other 'oiled' air filter? If so, maybe consider using less oil as it may be contaminating the MAF.
If the MAF has stuff on it, you can generally see the 'stuff' as a very small clot on the wire.
I think the wires may be somewhat questionable or the connectors/connection at the MAF. Take a close look, watching for chafed insulation, wires that have flexed a lot, and have broken some strands, or corrosion.
Have you looked at the spark plug wells, down where the actual plug screws into the head? If you have oil there, it will allow for misfire at idle and under acceleration. The cause would be bad cam cover gaskets around the plugs. They can harden and allow seepage. If you do have oil, the boots may need to be replaced as I don't think the dielectric works after being dipped in hot oil even if they are cleaned well.
tom

 

[Ave345]

Not sure what air filter but it sounds like a contaminated MAF or wiring could be the issue for me. I’ll be looking into a less oily filter too.