Rough Idle

[Rolln_Thunder]

2002 Ranger 3.0 (non flex) idles rough.
No codes showing

Replaced spark plugs and wires, also replaced both upstream and downstream O2 sensors.

No issues while driving - no hesitation, acceleration is fine whether slowly applying throttle or "punching it".
No stumble when letting-off throttle either.

Only the rough idle.

 

[graff104]

iac valve probably needs to be cleaned or replaced.

 

[fourwheelford]

You can clean that thing?How would you go about doing so?

 

[Runnin'OnEmpty]

Remove it and spray it down with carb cleaner
or brake cleaner. Then wipe out as much carbon
as possible, and give it a final spray of WD-40
for lube. Go easy with the spray on the electrical end
that contains the motor. The carbon build-up will be
on the pintle end.

 

[fourwheelford]

I have some TB cleaner will that work?

 

[fourwheelford]

I cleaned it all out, it was gross and all full of carbon build up I spent and hour cleaning that little bugger a mixture of sea foam brake clean wd-40 and a bunch of Q-tips and now it idles better, thanks much for the info.

 

[Rolln_Thunder]

My IAC has been replaced with no change.
I'm thinking my coil pack is bad.

 

[rngr4x4beast]

maf could be it mys goin bad and i have a rough idle

 

[graff104]

Yeah try cleaning the Maf, but be sure not to use Carb cleaner or anything like that. Either electronic cleaner or there is also some special MAF cleaner some parts stores carry.

 

[Rolln_Thunder]

I would think the MAF would throw a code if it were acting up, but maybe?

 

[graff104]

I would think the MAF would throw a code if it were acting up, but maybe?

I have heard of other people on here where it wasn't bad enough yet to throw codes yet they still had a pretty rough idle. When was the last time you changed your fuel filter? I'm just thinking aloud but could it be partly clogged causing a rough idle, but not noticeable while driving?

 

[NJRanger94]

I had the same prob it was my maf and i didnt have any codes also it may be the iac valve

 

[Rolln_Thunder]

Replaced the coil pack and it runs great - thanks to all who replied.