Hello XJ family, I want to start by saying thanks for any help.

I have and 87 XJ 4.0l auto 200k mi, built at 100k. I have also already searched many threads and forums, none fit.

It starts fine and runs normal, cold in the morning in Colorado winters (10-30degs.) Ill drive it to class about 1.5miles, class duration is between 3-5 hrs.

When I start it to drive home, it will fire right up but it will get "stuck" on 3000rpms and not cut down to normal idle. ive sat for 15-20 mins to see if its stuck or just has excess fuel from a leaky injector but no such luck and I don't want to hurt the engine. So I cut it off and then try to fire it back up. At this point it will not turn back over unless it sits longer.

Then I have to hump home on foot, let it sit for a few hours, then bring it back home.

Also if I simple try and drive it while its "stuck" at 3k rpms, it still wont cut down to normal idle.

Thanks everyone

 

Welcome to the forum.

Although you have a Renix, and there are some wise people on this forum regarding Xj's from this era (and I'm not), just some more general info on your problem.
High revs possible causes: IAC dirty, sticking throttle body valve, faulty TPS, vacuum leaks to name a few.
So, a good start is starting with cleaning the IAC and throttle body/valve and check for vacuum leaks. If this does not resolve the issue, checking the TPS is a good thing.

Cruiser54 is one of the Renix experts on here and in his signature there is a link to a wide variety of helpfull Renix (mostly) advice/things-to-do.

Do a search on the above procedures, they have been described extensively in other threads. See how you go, others will chime in.

 

Hey buddy thanks!
That's the route I was heading towards. ill be getting to it tomorrow. so after ill posts updates.

 

Updates are important!

 

Update... Stock IAC was going out. Put a new one in real quick today before the Superbowl. Jeep runs great (with a few hot engine turn over tests), but the true off and on test will be this week. Go Broncos!

 

Sounds promising. The IAC and throttle body cleaning are good maintenance items to do anyway.
Let us know if any issues recur and we'll look further.