the warmer my xj gets it idles higher and higher any suggestions?

 

check the IAC

 

maybe spark plugs.

 

Look at the vacuum lines too.

 

check manifold bolts...

 

Willing to bet you will find it's an intake/exhaust manifold leak ..

 

jeepster11 - is on the money

 

My bet would be a vacuum leak. Your TPS is trying to compensate for it.

 

it could be alot of things. mine was doing this forever till i ran alot of injector/fuel system cleaner thru it i mean like 10 bottles, and replaced the injector w one from the bone yard that sprayed right.i also had my intake and exhaust manifolds off to fix my exhaust leak. so it could have been leaking by the intake. i have a 2.5 but the 4.0 is very similar check all your intake bolts as stated. find out what "seafoam" is and use it. apply thru the brake booster this will clean intake, valves and stuff and sometimes its all it takes. it makes a nice smoke show and it usually nets a noticeable change in performance no matter whats going on with the motor so u cant lose by using it.
SEAFOAM FTW!!!!!!!!!!

 

iac is fine but whats the best way to check intake