[Tonyz 88]

Hi all,
I have an 88 dakota 3.9 ,2wd,a/t.

When I let off the gas coming to a stop I'll get about a 100 to 200 rpm cycling a few times then it will settle down. I've changed the tops, fuel pressure regulator, checked what vacuum lines I could and everything seems to be airtight. I DID smoke test the vacuum system and the bottom butterfly shaft has a small leak. I've taken apart my idle solenoid and greased everything. But you can see it pulsing when I do a quick rev and release. Any ideas?


Thanks for the help

 

[Tonyz 88]

It wasnt the tops I changed...it was the tps. Sorry, autocorrect.

 

[immattj]

Here is a thread/topic that MIGHT be applicable and that you might find interesting.

Scavenging and high idle at random times.

I have a 93 dakota, 2WD. The issue(s) I seem to be having are specifically after I've parked it at random times it likes to scavenge, Some days more severe than others. It will also idle at around 1k rpm to 1500 rpm and hold steady, Sometimes blipping the throttle takes it away and others it...

www.dakotaforumz.com

Basically it discusses a idle "hunting" condition caused by a vacuum leak which often originates from the intake plenum gasket leaking (which, I understand, the 3.9/5.2/5.9s are famous for).

Bottom line seems to be that if you look down the throat of your TB & note oil pooled up on the bottom of your intake, the plenum gasket is the culprit.

 

[Tonyz 88]

Here is a thread/topic that MIGHT be applicable and that you might find interesting.

Scavenging and high idle at random times.

I have a 93 dakota, 2WD. The issue(s) I seem to be having are specifically after I've parked it at random times it likes to scavenge, Some days more severe than others. It will also idle at around 1k rpm to 1500 rpm and hold steady, Sometimes blipping the throttle takes it away and others it...

www.dakotaforumz.com

Basically it discusses a idle "hunting" condition caused by a vacuum leak which often originates from the intake plenum gasket leaking (which, I understand, the 3.9/5.2/5.9s are famous for).

Bottom line seems to be that if you look down the throat of your TB & note oil pooled up on the bottom of your intake, the plenum gasket is the culprit.

Found the issue, thanks everyone...pinhole in MAP sensor vacuum line.

 

[immattj]

Thanks for the update!