Damon Owen

Over the last couple years my 2001 4.0 4x4 seems to idle a bit slow when I shirt to N or P. I recently chased down a PO401 code (swap out the DPFE-EGR was fine). I don't think the 401 was related. Ran fine w/ the code, runs fine w/out.

Seems now that if the motor is warm, if I shift through N or P w/out feathering the throttle she stalls out. Idle is smooth, if I inch the throttle a bit, but but even when i park and slide the shifter through N it will stall before I get to park.

I cleaned the MAF sensor, no effect. If the motor is cold it idles in N and P fine. There are no error codes. When I unplug the battery (reset codes) I think it runs fine for 10-20 miles, but then gets grumpy again (may be that it just warmed up and now stalls-not sure yet).

Maybe voodoo vacuum stuff? Anybody seen it?

R.S.LOGAN

Tried cleaning idle air control valve ?

Damon Owen

Not yet but I'll give it a go. Thanks for the tip. I will post results. Carb cleaner or something more fancy? Just bought a can of MAF cleaner...

R.S.LOGAN

Sensor cleaner / electrical cleaner /maf cleaner all o.k , if there is a lot of carbon build up in there it may take a few sprays .

Damon Owen

I cleaned the idle air control valve pretty well w/ MAF cleaner. Seemed to do the trick for a couple hundred miles. Crusty fine dust on the upstream side and greasy carbon buildup on the downstream side. After a good weekend trip in the hills the idle seems to be slowing down again. iI was a bit ginger w/ the MAF cleaner, maybe I will pull it off again and really saturate and clean it out well.

Maybe a better cleaning will do the trick-it deffinately solved the problem for a while. Thanks again for the suggestion.

I had a buddy suggest the foward O2 sensors, as the condition only arises when the motor is warm. There are no error codes at all. I will reclean the idle air valve 1st. Alot cheaper then throwing o2 sensors at it and hoping.

R.S.LOGAN

Well worth giving the idle air control valve another good clean out as you suggest .