ok,i give up on the rough idle

[snooper0069]

well looks like the 1993 4.0 does run rough from the factory after all. this was told to me by the ford dealership and i refused to believe it. after speaking with numerous mechanic shops i was told the same thing by them . oh, one good thing atleast ,i did get rid of my check engine light . it was the fuel pressure regulator. i changed this and no more check engine light.
as far as the rough idle ,it seems i have to live with it.

 

[EliteConcept]

have u tried checkin your sparxx plugs

 

[dogfriend]

cars are like people

some are a little rough around the edges

I had an 89 Ford Ranger (2.9L V6) which I bought with 17 miles and sold with 125k miles 12 years later. It idled rough after about 35k miles. I looked for the cause for a long time (vacuum leaks, ignition parts,O2 sensor, injector cleaning) but it always had a little bit of a shake and rolling idle.

Eventually I got over it because it always passed smog checks (to the surprise of the smog techs) and got good mileage. I think that maybe it was set a little lean at idle. It could have been a vacuum leak, but I was never able to find it.

 

[mrboyle]

Did you change the plugs after fixing the fuel pressure regulator? If not, take your X for a nice long drive. Give it time to warm up and run steady at 2000-2500 RPM for several miles. This will give the plugs a chance to clean up and burn off any carbon that may have built up when the pressure regulator was causing the injectors to dump too much fuel into the engine. If one or more of the plugs has carbon build up on it, it will cause the engine to idle rough.