Ok....had my 91 XJ for about a week now....first start...normal rpm, warms up, starts idling around and up to 1100....where to start...and how to fix....I've read on here about ppl checking "vacuum lines"....and also does anyone know what a little oil in my air box and on my filter is all about???

 

take a can of brake cleen and spray around and see where your leek is and about your air box and filter it probaly just a really old filter and has a ton of crap in it ie oil,salt,sand,and road debrease

 

The oil in the airbox is related to one of two things.

1. Blowby, compression blowing past the rings.
2. Plugged up vacuum port on the valve cover, or plugged vacuum line.

As to the idle, it could also be an idle speed motor not working. Its on the side of the throttle body.

 

Is there anyway to adjust it??