I put a brand new Airfilter in a stock box. today after a really hard day of driving rush hour traffic, I started it up again, to go somewhere and it ran really rough almost dying out, i kept her going by feathering the throttle. I shut it off let it cool off a bit more, noticed the oil in the AF box coming from the hose connected to the front part of the valve cover. It ran fine after it cooled I drove it for another hour 70 mph back home seemed to work just fine. ANy ideas on why there is oil in the af box?

 

I asked the same question in the oem section if the xj has a pcv valve then it could be bad and that could be the culprit but besides that idea I'm clueless 2 if u find out something let me know please sir thanks

 

Oil in the air box is usually a sign that the breather line from the intake to the valve cover behind the throttle body i believe its the ccv line is clogged

 

it actually sound like the heat soak issue, did you start it up again after 10-15min of hard driving and it ran rough?

 

your rings are bad its all from blow by gases

 

This is definitely not stop 1 for this question. There are a bunch of other possible causes, mostly mentioned above, that should be checked before thinking this

 

Yes exactly what I did, noticed it running rough and shut her down, let it cool for 45-60 minutes fired right up and drove 70 miles with out any symptoms

 

Checked cylinder compression, that ain't it. Good guess though.

 

check these out
https://www.cherokeeforum.com/f2/mis...der-3-a-82213/
http://www.go.jeep-xj.info/HowtoIntakeShield.htm
read through them and see if you are in the same boat, the info is nearer the bottom on the second link