Engine will not idle?

look for vacuum leaks. also could be malfunctioning IAC valve. you might wanna check your plugs and wires and coil(s) also.

These guides can help us fix it.

https://www.2carpros.com/articles/stall-at-idle

and

https://www.2carpros.com/articles/idle-air-control-valve-service

I know this ain't you, yours is very, very similar. This will sorta guide you to what you have to do, it is really EZ to do! Yours may be on the side of the throttle body and may have 4 bolts, my wifes' is on the top and has 2 bolts. "It could be the IDLE AIR CONTROL(IAC)", as he pointed to it, and emphasied it with a sharp rap using the wrench in his hand. It straightened right up, and ran darn good!!!..............That was a 15/16 Craftsman wrench, box end, kinda a medium rap. We removed and cleaned it, it may have gone on for a lot longer. Since it was my wife's, I took no chances.........YES, I visited parts store and replaced it, figgered it had 100,000 miles on it, and this was preventative maintenance in my eyes..............Hope this helps. Cleaning would be FREE, and at least Maybe take this factor out of the equation. The Medic

Thanks for the help guys. I replaced the Plugs and checked for a vacum leak. No leak found. The weird thing is, it still won't idle and runs really rough below 1500 to 2000 rmps. But if i rev it up it sounds normal but smells really bad out the exhaust. Any thoughts? Thanks again.

This sounds like one of your fuel injector is stuck this guide can help us test

https://www.2carpros.com/articles/how-to-test-a-fuel-injector

Please run down this guide and report back.

lol. Thanks Medevac. the guide showed me how to find the bad injector which was #3 I got a new one engine does great and my gas mileage is better. Thanks

Nice work, we are here to help, please use 2CarPros anytime.

THE MEDIC

i have just bought a 1995 Jeep Cherokee Sport(my 1st Jeep) which has been running excellent, until recently. suddenly it will not idle properly, will somtimes die, has acceleration problems and the rpm will occasionally race without speed increase. i have changed the fuel filter, plugs, wires, rotor, cap, and cleaned the throttle body. after cleaning the TBI it ran well for a while at an idle and for 2 long test drives. then agin suddenly, the same thing! any ideas or suggestions?

Check the idle air control motor, throttle position and MAP sensors. Also is the tranny slipping??

[quote:5b901d5f67="rasmataz"]Check the idle air control motor, throttle position and MAP sensors. Also is the tranny slipping??[/quote:5b901d5f67] i dont think that the tranny is slipping. although it did strike me funny that the RPM can race while driving but not increase speed.

i could not find in the manual information on the idle air control motor. could you please explain this further? and i have read on other forums to check the fuel pressure to make sure the pump is operating properly. i was always under the impression that a fuel pump usually works or it doesnt. could it be failing and sometimes work and then not? if so it would help explain why it ran fine and then started to act up again.

when starting the jeep, sometimes i have to keep my foot on the accelerator to keep the jeep running. The idle will not idle smoothly. It wants to die. If I am driving out on the road it seems to be fine. Only happens when I am driving at a slower rate of speed (city driving)

Inspect and test the idle ar control valve/ EGR valve and throttle position sensor.

[quote:797e34f890="rasmataz"]Inspect and test the idle ar control valve/ EGR valve and throttle position sensor.[/quote:797e34f890]


hi my name is rahmel i been a mencanic for 4yrs,my sister has the same truck and the same thing ur truck is doin hers was too.so wat i did was change the idle air control valve and drove the car for a while.so if i was you i will change thats beleve me thats wats wrong.after u must drive the car for a while it has to relearn its self

HELP!! I have a 1993 Jeep Cherokee 4.0 that now has trouble idling. It started about two months ago when I was driving it would stall(Be driving 60 and all the sudden RPM's would rev up but with no acceleration). Over time it got worse and now it won't idle for more than five minutes and as soon as I step on the gas, it rev's and then wants to die. People on other boards told me maybe my CAT converter. So I removed and still won't idle properly. Was told it could be my fuel filter so I replaced and still nothing. Ran some Injector cleaner through and still nothing. My fuel pump is turning on and pumping but not sure at what PSI. Also cleaned my throttle body with cleaner. Replaced the sparkplugs. Need help on a limited budget, was just laid off from my job and I need this vehicle. So I can't afford to take it in and have them replace a bunch of stuff that it may or may not need. Thanks for the help guys.

Lets start by checking the fuel pressure-if okay test the idle air control motor,throttle position and manifold absolute pressure sensors. Also check the PCV and EGR valves/Test the camshaft and crankshaft postioning sensors.

Two days ago my jeep cherokee has started to act up. It started with it "bucking" when I drive it and now it stalls when I am driving it at low speeds.

If the check engine light is on, have the computer scanned to identify trouble codes. Also, check fuel pump pressure to make sure it is within the mfgs recommendations.

Jeep starts fine but will not idle. If I disconnect the vacuum tube to the map sensor, it will idle fine until the thermostat opens up and then it will stall. The map sensor and the ecm are new. The egr valve is not stuck. The fuel pump is also new and the injectors have been serviced.

[quote:cd50906d5e="Al 507"]Jeep starts fine but will not idle. If I disconnect the vacuum tube to the map sensor, it will idle fine until the thermostat opens up and then it will stall. The map sensor and the ecm are new. The egr valve is not stuck. The fuel pump is also new and the injectors have been serviced.[/quote:cd50906d5e]

Hey al,
Your symptoms lead me to say that its possibly a coolant temp sensor.

Regards,

Chris

I have a 99 cherokee sport (4.0) with 150,000 miles. Occasionally it will not idle. If I hold the idle myself until the engine warms up(5 min) then it will idle. I ran a scanner po 505 came up. I recently replaced the idle conrol motor but this has not solved the problem. What else can it be?

Just a few thoughts.
Did you disconnect the battery? You might need to reset the computer by disconnecting the negative cable.
Did you double check the connector and it's wiring?
Have you cleaned the throttle body and the IAC port?
Have you cleaned the EGR valve and it's port.

Have you cleared the code and had it come back?

Good luck and let us know. :)

I've just replaced the front brake pads at 110,000 miles. The problem I'm having is an intermittent inability for the Jeep to idle at startup. This occurs whether the engine is cold or warm.

What I've discovered is it will start and idle if I remove the hose that supplies vacuum to the brake booster. After a couple of minutes, I can reattach the hose and it will idle. It will also idle normally (eventually) if I rev the engine to about 1500 rpm for several minutes. From what I can tell, I have good brake pedal feel. I have replaced the vacuum check valve on the booster to no effect.

Any help would be appreciated.

To answer my own question: It was the battery.

To make a long story short, the battery had enough power to start the motor but not enough to supply the computer with the necessary current to function properly. Since the battery was replaced, it has been running fine. The brake change was just a coincidence.

Glad you got it fixed.

Roy