powerfulpup
New Member
Hey all, been lurking for awhile, and have found this to be a great resource
Now I'm a bit stuck, so I registered to ask the (wiser than myself) masses.
My 1999 manual transmission Ranger 4.0L, with 123,000 miles on it, has started to idle rough when I put in the clutch. After searching through many related posts, I'm kinda thinking my IACV is in need of a cleaning, or replacement, however my symptoms aren't exactly the same as others have experienced, so I thought I'd describe them and see if you thought that was still the culprit.
The two other things I had considered was the EGR, which I eliminated because supposedly that is closed/off at idle (or so I read), or the mass airflow sensor, which just didn't seem as likely to me, but I'm far from an expert.
- Occasionally starts a bit hard. Has never NOT started, just takes an extra crank or two sometimes. Sometimes will idle very low for a few seconds after starting before getting up to normal.
- When I engage the clutch to de-celerate, say from highway speed, the idle immediately drops. Cabin lights dim, RPMs are down to just a few hundred, then it'll surge back up above 1K RPMs, then drop, then surge, then drop, and after a few seconds will settle back to a normal idle. It has never died on me.
- Occasionally when I engage the clutch, rather than a drop in idle, it'll surge to about 2K RPM and stay there for several seconds before settling down. If I blip the pedal just a bit, sometimes this will cause it to return to normal, but not always.
I don't really detect a whining or "fog horn" noise that some have described. Also, none of these things happen 100% of the time. Intermittent problems are the bane of my existence. After it settles down, it is fine until I move and stop again, then it goes through the whole production again. So if I am going through a series of stoplights, it's kinda disconcerting. It is winter, snowy, and cold here. Most mornings are in the single digits or teens, although below zero has happened several times. This problem never occured last winter, and hasn't started until this winter. I'm not sure if that is a coincidence, or a cause.
Thanks for any insight anyone may offer.

My 1999 manual transmission Ranger 4.0L, with 123,000 miles on it, has started to idle rough when I put in the clutch. After searching through many related posts, I'm kinda thinking my IACV is in need of a cleaning, or replacement, however my symptoms aren't exactly the same as others have experienced, so I thought I'd describe them and see if you thought that was still the culprit.
The two other things I had considered was the EGR, which I eliminated because supposedly that is closed/off at idle (or so I read), or the mass airflow sensor, which just didn't seem as likely to me, but I'm far from an expert.
- Occasionally starts a bit hard. Has never NOT started, just takes an extra crank or two sometimes. Sometimes will idle very low for a few seconds after starting before getting up to normal.
- When I engage the clutch to de-celerate, say from highway speed, the idle immediately drops. Cabin lights dim, RPMs are down to just a few hundred, then it'll surge back up above 1K RPMs, then drop, then surge, then drop, and after a few seconds will settle back to a normal idle. It has never died on me.
- Occasionally when I engage the clutch, rather than a drop in idle, it'll surge to about 2K RPM and stay there for several seconds before settling down. If I blip the pedal just a bit, sometimes this will cause it to return to normal, but not always.
I don't really detect a whining or "fog horn" noise that some have described. Also, none of these things happen 100% of the time. Intermittent problems are the bane of my existence. After it settles down, it is fine until I move and stop again, then it goes through the whole production again. So if I am going through a series of stoplights, it's kinda disconcerting. It is winter, snowy, and cold here. Most mornings are in the single digits or teens, although below zero has happened several times. This problem never occured last winter, and hasn't started until this winter. I'm not sure if that is a coincidence, or a cause.
Thanks for any insight anyone may offer.