99 Cherokee Full throttle HELP

So I havent been posting in a while but a week ago I bought a 99 Cherokee 4.0 Auto 4x4.
My problem is that it had a crack in the header so I took the intake and everything apart to get the header off and then I welded it and put it all back together.
I started it up and the RPMs went to redline so i shut it off. I checked all of my connections, the throttle cables, and made sure the throttle wasnt depressed and started it again. Same thing happened, it fired up and the RPMs shot all of the way up. I am confused as evrything seems to be hooked up correctly. I cleaned the injectors and put di-electric grease on all of the connections while re-assemling. Any thoughts? Suggestions? similar issues? Thanks for any help, this is the best forum I have been on IMO!!!

Common enough occurrence, usually resulting from not getting the intake manifold fully seated on the alignment pins, i.e., a massive intake leak.

you have a very large vacuum leak somewhere. most likely the intake hung up on the locating dowels, and didn't seat properly. check from underneath. hopefully the intake isn't actually cracked(seen that twice now).

edit: quickdraw peters beat me again!

I would bet you guys are correct, I didnt even notice locating dowels. I did this same thing on a 94 ZJ and jsut bolted it right up with no problems. I will check this out tomorrow. Thanks for the quick reply gents.

I had the exact same thing happen to me, except mine was with an APN exhaust manifold, not the original.

Here's a link to that thread:

http://www.naxja.org/forum/showthread.php?t=979438

Good luck