I have the manual tranny AND cruise

 

U wanna trade id love to have a manual again at least as a dd and mud rig but on the rocks id rather have my auto i think

 

Hello, guys my I am having similar problems with my 98 jeep cherokee xj I just recently changed the cylinder head after I finished putting another one back, i got everything done and then I I fired it up the rps who all the way up its accelerating byitself hard as if I was putting the gas pedal all the way in. I first disconected the cable and then then all the connectors that go to the throttle body and still does that thinking it was the idle air sensor but no, vaccum line either .... what do you guys think it could be.

 

Here's something you can check. Disconnect the throttle cable at the TB and try pulling/pushing it. Chevys had a tendency to break wire strands inside the cable cover and cause sticking.

 

If the throttle plate is closed and it's revving, it's getting air from somewhere else. Did you use the same manifolds, and did they go on nice and flush? Maybe you missed something like the line to the power brakes....even the EGR I suppose might be an issue. It can't rev without air.

 

It's actually the idle air control, hence, "IAC". It has a rubber sort of ram thing controlled my a motor, getting instructions from the puter'. It let's air pass the throttle plate. In the old carbed days we had control with the idle speed screw, how much air passed. Now we have that.... They are easy to muck up, for instance if someone powers it up with it out, it might run that ram out to the end of it's threads and blow the calibration. ( I'm making this up now). If you rule our other sources of air getting in to let it rev, trying another IAC might help...Idk.

Welcome to CF Javier.. Wow a thread from 3/13! Wonder if any of them are still around...