I reset the computer. It was idling at about 1200, so just a little high. As clogged up as intake and head were, maybe the computer is still learning the new unrestricted flow of air and fuel. I let if run for about 15 minutes then drove around. I did fit them on the bench before install. I was able to see exactly what needed to be done.

 

1200 = vacuum leak = lean. Unless your TPS/IAC is screwed the computer will do its best to idle at 750.

 

X2. Start the Jeep and slowly pour water over the intake manifold from front to back where it meets the head soon as the idle drops you have found your vacuum leak. Most Likely it's the #1 or 6 cylinder. Your header should not glow.

 

Ok. Thanks. This morning it would idle at 900 or so at first start up the climb to just under 1100.

 

Just figured out, using the water trick, that the intake manifold is not seated properly at #6. Guess I will be pulling that off tomorrow and doing some more work on it.

 

Good to hear, that water trick is an old mechanics trick. IIRC the Jeep FSM tells you to use that method also to diag where a leak comes from. But the 4.0 is also a ancient engine

 

Yes, it does work. I did fix the leak. I loosened all of the manifold bolts, gave it a wiggle, then got in there with a little more leverage (cheater bar to get some more leverage) and made sure all of the bolts were "torqued" down pretty good. No more leak, idles at 750 RPM just like it is supposed to.

I am glad I did not have to pull it all of the way off again.

 

great to hear. That's how I got mine on !

 

I really think the issue was the bolts were not tight enough. It all fit perfect on the bench, so I was pretty mad when it was leaking yesterday. The bolts on the bottom were hard to reach until I laid down under the Jeep and reached up as far as I could to get wrench on them then put a piece of pipe over the wrench to get enough on them to tighten them down. Doing it from the top I was not able to get them as tight as necessary. At least that is what I am going with since it is all good now.

 

I used some long handle ratcheting wrenches to get the ones on the bottom from under the jeep

 

I can see where those would be beneficial.

 

So here's a question. I did a little grinding on mine over the weekend hoping to maybe get cracking on it this week. If you get the exhaust manifold in and you need to tweak it, do you have to pull it out, or could you install some "precision dimples" on the 6th runner while it is in if there is interference?

 

I don't see how you could do any work on them installed. The problem areas are between the header and the intake manifold which you cannot get to when installed. I believe you would have to pull it out to do it.

 

I guess I could have been more clear. I know you couldn't do it with the intake installed, I was curious if you could do it after pulling the intake but leaving the APN mounted.

 

Gotcha. Yes you can do that.

Take a look at post 55559.
https://www.cherokeeforum.com/f59/wh...940/index3704/