A little confused/frustrated
while that makes sense, a blown intake gasket is pretty unlikely, since they are a steel mesh like gasket, that kind of crushes...if you havent done any intake/exhaust manifold removal thats probably not the problem. if you go out to your jeep and pull the vac hose off your brake booster it'll rev up that high. which leads me to believe its a vac leak.
there are a few different vac lines attached to the intake..there is a small (about 1/8th inch diameter) black plastic like line....it could be cracked....there are 2 more rubber hoses (about 3/8ths or so thick) and there is the one going from the brake booster to the intake...its probably not that one, but its probably going to be one or more of those 3
CF Veteran
Joined: Mar 2010
Posts: 1,030
Likes: 2
From: Elizabethtown, pa
Year: 1994
Model: Cherokee
Engine: 5.2
start the damn engine, and spray throttle body cleaner around the intake, when the idle changes that is where the leak is. Short and simple, works everytime
I've tried all of the above suggested fixes with no luck. I don't want to take it to a mechanic, but need it running by 2p tomorrow. Not sure what to do at this point.

CF Veteran
Joined: Aug 2010
Posts: 2,112
Likes: 4
From: Wantage, NJ
Year: 1995
Model: Cherokee
Engine: 4.0 I6
New IAC, new TPS, new MAP and it still idles @ 3000rpm. I'm ready to cliff this thing into a river! I am seriously out of any answers. I dont see any signs of the vacuum line leaking. The line towards the front of the motor just goes to the air cleaner and thats not clogged. Could the vacuum line be bad and I cant see it?
Injectors is a possibility, Id go ahead and check them along with the Fuel pressure regulator, alternator and reset the PCM. If the fuel pressure is to low the ECU would raise the idle speed to accomodate. If the alternator is going bad the computer could attempt to make it idle higher to achieve the correct power output.
Last edited by Diesel; Sep 22, 2010 at 07:33 AM.
I don't get this. An OBDII code is a number. Not trying to be a PITA but it may help figure out the problem.
I hate to say it, but it sounds vacuum-y to me as well. The rubber boots can start to deteriorate, and I think Ive seen the hard plastic ones that like to snap in half develop cracks down the length of the line, making it hard to spot.
I hate to say it, but it sounds vacuum-y to me as well. The rubber boots can start to deteriorate, and I think Ive seen the hard plastic ones that like to snap in half develop cracks down the length of the line, making it hard to spot.


