The engine was idling fine to begin with, besides having a miss. I changed plugs, wires, cap, and rotor, then cleaned the throttle body and reinstalled with a new gasket. While cleaning the throttle body I noticed alot of carbon aroung the IAC spindle. I removed the IAC and cleaned it really good. I mean this thing was shining when I finished. When I reinstalled the throttle body and started the Jeep it started running at around 3000 rpms. I shut it of and worked the throttle a few times started it up and it started idling funny. It will idle back and forth between 500-800 rpm's. Today I checked the TPS with a volt meter and it was slightly off. I got it back to specs and restarted the Jeep. It again ran at 3000 rpms. I turned it off and again worked the throttle and restarted it, and it is still running between 500-800 rpms. I looked for a vacuum leak but cannot find one. Any ideas???

 

Triple check for vac. leaks. Make sure there are none, unhook the battery for a couple hours to make sure the comp. is reset for the cleaned IAC.

 

X2-Disconnect battery. Usually just 30 minutes is fine in my experience.

 

The renix jeeps don't store codes....... Disconnecting the battery just resets your radio. That's it.
To the OP yes check for vacuum leaks again. Also check the exhaust manifold bolts. On my '90 one of the bolts was loose. I tightenend it up and magically it brought the idle back down.

 

Make sure your intake manifold bolts are snug.

Which side of the TPS did you use for adjustment? Flat 3 wire connector or square 4 wire?

Ever refreshed all your grounds? Some real critical stuff relies on one ground in particular.

 

Agreed, it doesn't store codes (no one said that), but it does reset the ECU and TCU.

 

Well like I said it was running fine before the tune up and throttle body cleaning. So in theory the grounds should be fine. And also in theory the only way I should have developed a vacuum leak is if something became disconnected while I pulled the throttle body. All of that is fine, I have checked the vacuum lines about 4 times now. I am leaning toward thinking it is something associated with the throttle body since it started acting up when I removed/cleand it.

 

The common denominator is the plastic tube with 2 rubber ends between the throttle body and MAP sensor.

And FWIW, if anybody owns a Renix and doesn't know for a fact that the ground refreshing has been done, they need to do it themselves.

 

Left the battery unhooked most of the day. Worked like a champ. Thanks!

 

Oh okay, I just figured that since it doesn't store codes it just resets itself everytime the jeep is turned off.