As title states on my 98 jeep cherokee after i did the 99-01 intake swap and new apn header, I started it up and the throttle just goes full bore WOT. I unplugged the map sensor and I have to feather the gas to get it to barely run. But when i plug it in it goes full bore once again. I reset the computer as well. Im lost. Any ideas, any help is appreciated. Thanks guys.

 

Your intake manifold is not fully seated and creating a huge frickin' vacuum leak which in turn makes your engine run at full throttle.

 

That, or your throttle cable is hung up somehow. Could be your map sensor too, you said it was better with it unplugged.

 

It's the intake leak.

 

Agreed, It's an intake leak, I had the same issue after my head swap. The manifold just didn't want to seat properly, and it took a little work with a dremel it fix it.

 

I would agree with the intake leak. look at the intake by cyl 6, I would guess thats the problem area.

I laid a 6 inch extension down on #6 exh tube and hit it with a hammer, rolled it a little more and hit it again until it cleared and rolled the very top of the tube where it hit flat to clear the intake about 1/8-1/4". The intake hits the tube on the underside of the intake the furthest back and wont let the intake sit flush and down all the way on the head. (wouldn't on mine anyway 7120 head, APN manifold and 2000 intake)

I took some metal off the intake, but didn't like how thin it was going to be after grinding it to clear. which is why I flattened the tube slightly, wont effect anything doing it that way either.

 

Alright guys thanks look like i will be tearin it apart again today after work. I will let you all know how it goes.

 

Alright guys its up and going thanks for all of your help. I did what Gorillaxj did and now all is well.

 

Kind of weird how many people say they had this issue, I never did. Maybe its because I have the stock header?

 

The APN manifold sticks a little higher and hits the intake on cyl 6 tube with the newer intakes. a stock manifold shouldn't have any clearence issues.

 

^x2