I'm trying to revive an 89 xj. Now that I've got it running, after starting, it idles at 250 then rapidly climbs to 2000rpm. It takes a good 10 min or more to come down to 1000 where it stays. I've replaced the IAC and the TPS, cleaned where those connect to. There doesn't appear to be an air leak anywhere that I can find. I cleaned the ground connections. Please help

 

Mine was doing the same thing a while back. Try this, tighten intake manifold bolts. Can almost count on having one or two loose. Crank those babies down.

 

@Zim earlier today I found an exhaust bolt looses tightened that bad boy up and now it's running smoothly. Wish I made this post weeks ago. Thx for your response

 

While you're at it, click on the pink link in my signature below and do Tips 1,3,4, and 5.