Stalling on 1989 Cherokee 4.0L

My 89 Cherokee with 4.0L inline 6 idles smooth, runs fine at all speads but will stall when creeping along at an intersection or if you start and then stop off from a complete stop, I have done all the mechanical step I can think of
Clean Throttle Body
Check for vaccum leaks
New Ignition Parts Cap Rotor
New Properly gapped spark plugs
Replace fuel filter
Replace the fuel pressure part on the fuel rail

The only thing I can think of that it's electric and must be the computer controlling idle etc, I do not have a repair manual, can anyone give guidence as what else to do, where is the computer controller on this vehicle and how much would it cost to replace

might possibly be an O2 sensor......sounds like the symptoms

recently passed smog test here in California, wouldn't a bad O2 Sensor fail the smog test?

Dealing with something similar on my 87. Sometimes it'll take a spell and run like just off the showroom then it'll go back to a choking sorta deal at low rpm acceleration and stall. Usually when that happens it won't restart till it cools completely down to cold then will restart great.

test, clean, etc of IAC ?

ECU from Azone... about 100 bux exchange

But test test test before spending$$

there are some threads on here with similar issues.... could even be the EGR...


test....

Read up on the throttle position sensor here for test procedures with a digital multimeter. It could be a bad spot near the idle position on the TPS wearing out on the carbon resistor area of the TPS, or a problem developing with IAC or the wiring /connectors between the IAC/TPS and the ECU. My first bet would be the TPS going bad.

Also check the reading (resitance, ohms) from the battery negative post to the engine block, or valve cover, and to the firewall. They should read less than 1 ohm. If higher than 1 ohm, like 10 or more ohms, then remove the ground connections on both ends, clean and reinstall the ground wires from the negative battery terminal to the engine and firewall, until you get down to 1 ohm or less.

I think I am experiencing very simular problems with my 1990 cherokee, i did everything you have done, cap & roter, plugs and wires, oil change, fuel injector cleaner, WOT or "throttle position sensor". Nothing seems to fix it but mine did get a little better. mine is in rough shape, i live in michigan and my exahust has about had it. The only other thing i can think of changing is the fuel pump. the only other thing with mine is the o-ring on one of my fuel injectors is bad and leaks half of the time. thats where i am at with mine.

no one has mentioned the cps?

Everyone is describing a sticking/bad EGR valve.