Jeep Erratic Idle

Hey All,
I recently had a problem with my Jeep running very rich and not running
quite right. Well that was finally fixed last night when a hole in the
vacuum line to the M.A.P sensor was discovered. Went and started it up
for the first time since I fixed the vacuum line, and it fired up
quicker than normal and isn't running rich anymore, but now it has a
fluctuating idle. It will idle between 900 and 2,700 RPM now. If I
disconnect the M.A.P vacuum line, it goes back to how it used to be and
idles, but runs very richly. Does anyone know whats going on?

is it trowing a code? is the engine light on? i could be another vacuume leak. go over all the vacuume lines. it could also be the 02 sensor. could also be your egr? im not sure.

I am going to have it checked for codes tonight. The Wagoneer isn't equipped with a check engine light. I was thinking it may be a vacuum leak, but I have been spending all morning looking and pinching lines and finding nothing. I tightened the manifold bolts hoping they were loose and nothing... Now what?

You didn't list the year model. The early renix based computers are not ODBII compatible and you won't get any codes. Eratic idle is routinely caused by a vacuum leak that changes with the phase of the moon. Careful cleaning of the IAC to remove gum and carbon can be helpful, just don't get the TPS wet.

old_man said:

just don't get the TPS wet.

Click to expand...

2nd that

also check your TPS by buying a new one, swaping the new one in, and seeing if that helps...

what you are describing sounds similar to my TPS issue before...

It's an 87. I was also thinking it was the TPS... all the symptoms seem to be leading to it. Thanks!