how to adjust idle ?
 

I need to adjust my a idle a tad but don,t know what screw driver it is,I can,t see.Is it stot ,torx etc.Is a 89 4.0 auto

I don't think you can adjust the idle on a Renix era XJ. It's all controlled by the computer. Amazing, considering that in those days ECUs were about as powerful as a calculator.

Not too familar with renix jeeps but check the IAC (Idle air control) valve, im assuming renix jeeps have one. It would be mounted on the side of the throttle body and if they get dirty it will cause a bad idle

Is your idle high or low? Don't turn any screws on the throttle body!!

Just once in awhile the truck will stall when coming to a stop,I did clean the IAC.Like I said is a auto.

At the back of T.B. where the throttle cable is you can see some threads to stop the cable and is a small hole where I think you would put some sorta tool in for adjusting

DON'T DO THAT!!!!

That is there to keep the throttle plate from digging into the bore every time you let off the gas. The blade is to be completely closed. The idle air is controlled by the IAC from computer input.

any other suggestions,air cleaner is new and spark plugs too,sea foam last week.

Have you checked for vacuum leaks? Adjusting the idle will only mask what is causing the problem and screw things up worse. Get that idea out of your head and focus on fixing the problem.

Make sure your intake manifold bolts aren't loose.

The CCV hose from the rear of the valve cover to the intake manifold has to be in good shape. Not crudded up, melted, cracked or have loose fitting ends.

Your TPS could be bad or out of adjustment.

Your sensor ground circuit could have bad connections.

The hose from the throttle body to the MAP sensor could be crappy. Check it like the CCV hose needs to be checked.

Did you clean the throttle body along with the IAC?

I flet the need to write the following just because some guys fought high idle issues because of "Uncle Bob".

Cruiser’s Renix Throttle Body Butterfly Adjustment
Okay. Let's start from scratch. First off, that's not an idle adjustment screw. It's a throttle butterfly stop screw. It's purpose is to allow the butterfly to be as close to completely closed as it can be without binding or wearing into the throttle body. It was never intended to be adjusted in the field. But, Uncle bob didn’t know that, did he?

Engine off. Back off the butterfly stop screw with a 3/32" allen wrench until the butterfly is completely closed. Now. turn the screw in until the FAINTEST movement of the butterfly opening is detected. This can be done more easily with the throttle body removed. If you remove the throttle body, be sure to replace the gasket underneath it after thoroughly cleaning the old one off.
Revised 07/07/2012

OK ,thanks,I will check all those things.Is my first computer inj. vehicle ,I,m used to the carb setups,nice and simple.I,m learning thanks to the forum

[QUOTE=blazer 2008;2041075]I need to adjust my a idle a tad but don,t know what screw driver it is,I can,t see.Is it stot ,torx etc.Is a 89 4.0 auto[/

So you can't use that Allen head screw to adjust the idle slightly higher?

[QUOTE=Dyno89;3156331]Nope its just there to set throttle plate gap.

Before monkeying with anything of the sort, make sure your intake manifold bolts aren't loose, you have new plugs, wires, cap and rotor, all the vacuum harnesses are intact, and you've done my Tips 1,3,4, and 5.