3.0 rough idle.

[Bryan22]

i've got a 92 with a 3.0 manual tranny. Runs like a champ but it idles really rough, no codes or anything fuel filters only like 10k old i haven't really started digging into it yet just wanted to get some starting points for things to check or clean. thanks.

 

[Just_Randy]

Does the check engine light work? Someone took the bulb out of mine.... Hard to believe the is any kind of problem without a CEL light on, lol. Usually they come on just randomly when the truck runs like new (seems like anyway).

If you have an EGR, pop everything off and clean it. Stick a new set of motorcraft or autolite DOUBLE PLATINUM plugs in and some new wires. I just dumped $200 in my engine chasing codes and nothing made it run any better except those plugs. Be sure your air intake plenum is tight all the way to the airbox! Can't have any air leaks if you have a Mass Airflow Sensor.

That's what I would do.

 

[Ranger44]

IAC could be bad, or clogged.

Codes are only generic. But are a good start.

If there are no codes a dirty EGR tube, gummed up IAC, foulded plugs, bad wires, clogged air filter, could be the culprits.

 

[Quiksurf]

getting inj flushed out of higher mileage ford seems to smooth out a few of the rougher idles from time to time

 

[Bryan22]

Thanks for the input guys, don't think this truck has an EGR system on it, plugs wires and air filter are all in good shape... i'll try cleaning the IAC today. Thanks again.