Ok guys...tech question. I put on my new APN exhaust manifold on my 4.0 tonight. Went on great with no problems. After finishing up I went to fire the jeep and the RPMs shot to red line. Had to shut it off to stop the motor from blowing up! Checked all the bolts/electrical plugs and they are good. So I'm stumped and need help!

 

Iac?

 

Double check. It's redlining because it wasn't seated properly against the head.

 

yes.

 

Seeing that you have a 99 you need to grind down the bottom of the #1and #6 intake runners. The intake is not seated properly thus creating a vaccum leak.


I have read About that issue a bunch on the 99's. I'll let you know how my install goes tomorrow when I get my APN Header on my 99

 

You're full of ****.

 

I'll take a pic when its done just for you ok.

 

Lol.

 

How bout for all of us. We've seen enough threads stating "when my headers go on"

OP, it's not seated right. Pull everything apart, get the grinder out, and try again

 

Make shure it seated on dowels right. I just had mine off after 5 years and when input it back on wasn't seated properly, and just like yours shot straight to red line.

 

I'd like to see a picture of the intake mani after being ground down... I have to do a header replacement soon.

 

Here's where you have to grind down a REnix intake when installing a header.

Keep in mind the manifold is upside down on the bench.

 

Here's where we ground ours on our 97. And by grind I mean very carefully filed. We also opened up the holes that the exhaust mani mounts with.

 

Forgot the picture!

 

My buddy just texted me that my header install is finished and it went on flawlessly. He did not have to grind anything. My XJ's build date is 6/99 so its a late 99 build