I'd like to start out by saying these are not vacuum leaks so please do not insist or even start to tell me how to search for them.


With the being said IV got 2 renix Cherokees with the high idle on start up. Here's some info:

1988 4.0 Xj
1990 4.0 Xj


Both are having intermittent high idle on start up. It started out not very often now it's almost every start. The idle is around 2500-3000rpms. If I shut the vehicles off and re start them usually it goes down after the 2 or 3 time.

Here's what IV done so far:

1990 Xj
-replaced iac
-recently replaced TPS
-replaced all vac lines
-cleaned throttle body
-reset factory butterfly set screw
-refreshed grounds

1988 Xj
-swapped in Spair iac
-will be replacing TPS tomorrow
-cleaned grounds
-cleaned throttle body



Like i said this isn't vaccum related. It only does it at start up, it will last as long as I let it rev for. It will usually go away after 2-3 starts. I'm wondering if I have actual harness issues.

I have also read online that it could be egr. What would the egr do to make the engine idle high?

 

I think there is a TPS adjustment procedure on the renix. You might want to search how to do that, if you have not done it already.

 

Cruisers Helpful Hints...https://www.cherokeeforum.com/f51/cr...x-tips-153657/

 

Classic faulty TPS symptoms.

 

The thing is on my 90 I literally swapped it 2 weeks ago. I guess ill take it back and have it swapped out again.

As for the 88, Im going to be doing that one tonight when I get off work.

How much is OEM TPS from the dealer? Im not sure i want to fork out tripple digets for 2 tps.

 

Will a bad TPS and high idle cause the vehicle to use too much gas and fail a smog test?

 

Why aren't you doing this yourself?

 

Had the same problem with my old 90 sport. Check the mass airflow sensor. Beside the tps. While the engine is running give it a couple taps with a wrench and see if it settles down. Buildup of gunk was not allowing the piston type lever to go in and out fluidly and was causing throttle to stick. Couple taps clears the gunk out and if she settles down there's your prob

 

Mass air flow sensor? Huh?

 

Lol IAC I think he means. I am doing it myself, I was asking if anyone knew the cost of the TPS from a dealer. Iv bought mine from Orielly and this is the 2nd time ill be warrantying it.

 

As for this, I wouldnt think so. Depending on how they test it the have to rev the engine to certain rpms anyways to get readings at that rpm. Also depending on which of your numbers are high would change where to start looking to fix.

Id start with O2 sensors and make sure your CAT isnt clogged.

 

If you want a deal on the TPS from a dealer, contact Scott McCall at York Jeep in Prescott. scottm@yorkdodge.com or 800-894-4970. Tell him Pete sent ya. 10% off factory list price and he will ship.

 

any idea what cost range of it might be?

 

Check with Scott. He'll take care of you.

 

okay thanks.