Idling really high

[landlubber]

Well, for at least a few weeks now, my truck has been idling terribly high. around 1500-1750 usually.

 

right when I start it up, it runs fine, but after a few minutes the idle creeps up and keeps getting higher. If I shut it off to get gas or something and then start it up, it does the same thing. Idles fine for a few minutes, then gets really high.

 

checked vacuum lines, tested 3 different MAP sensors, two IACs. I'm running out of ideas.

 

Was running with the Vac to the MAP unplugged, runs really rich, but idles ~600

 

video of MAP (vacuum) unplugged:

 

qnwC6_L860s?hd=1

[JeffN]

leave the map plugged in at all costs, check your intake bolts for tightness, if you have a bottle of propane hook a hose to it and spray it along the places that can leak vacuum like hose, where the intake bolts to the etc, etc and see if the idle changes.

If it changes where you spray the propane you found your leak.

A good place to start is manifold and egr valve

[landlubber]

I used a propane blowtorch to check for vac leaks. I've never touched manifold bolts. Been fine for the past few ten thousand miles.

 

I'll check the egr, and bolts and report back.

[landlubber]

Manifold bolts: only ones i used to hook the load leveler tpmwere slightly loose. Like 1/4 turn.

 

Nothing responded to the propane. Still idling at about 1700. Same deal.

 

I am at a loss.

[M1A1TankerTom]

same thing happened to me, turned out to be the manifold bolts were loose. Tightened em up and it went away.