1995 Jeep Grand Cherokee Limited Idle Problem

[maximumquake]

I have a 1995 Jeep Grand Cherokee Limited with a 5.2 V8. Also yes before anyone replies search the forum I have and I have aquired a wealth of knowledge on this issue I would just like someones opinon before I go putting more new parts on. When I first got my Jeep it had a low idle miss and sometimes when I would smash on the gas I would get no throttle response for about 3 seconds or so. My jeep also stalled on me only one time. Since then I have got a a complete tune up(new cap,rotor, spark plug wires, spark plugs, fuel filter, and my fuel injectors cleaned) I also replaced the o2 senor. Since doing this to my jeep, it runs great has plenty of power and the throttle response is great. But the problem is it still has a low idle miss. When I first start my jeep it runs fine it idles around 700rpms out of gear and about 500 in gear. But the problem is after I drive a little bit, when I come to stop or I am idleing in gear it feels like it has a miss; the rpms drop to almost around 200 or so and it runs very rough. Even when it is not in gear after I drive my jeep for a little while you can still feel the miss it idles at around maybe 300-500 rpms. But as soon as I give it a little gas(around 600 rpms) the miss goes away. My jeep runs great, I never have no problems with it and it starts everytime; except for the miss. I did a prior search before, on this issue and I thought it might be the 02 sensor but I was wrong. After talking to a mechanic friend of mine, and doing a search on here, both coincided and suggested it is the iac. Should I try replacing the iac next or could it be something else?

[Scrapper]

first of all i'd do a compresion test or take plugs back out and look at them should be able to tell witch plug is funny looking compared to the other one's if you do this it should tell you. it sounds like a valve to me unless bad plug or tps sensor,egr,iac sesor on idle.

[maximumquake]

I just read this "Problem #10 IAC motor

I have a 1995 Grand Cherokee with exactly the same problem. I just got home after stalling in a busy intersection for 20 min. The car has been in the garage and they were unable to find any problems. They cleaned the throttle body and the car worked fine for a couple of weeks

would agree it sounds like an IAC problem , b/c it only seems to do this when the throttle plates are closed, when the throttle is closed, the IAC opens to allow air to by-pass the throttle plates into the engine to keep it running.

try this to determine if the IAC is bad, start engine, place in gear (drive, Reverse), turn A/C on, and operate the power steering pump (turn wheel slightly right or left). the rpms should increase slightly or remain steady, if it drops or stumbles then the IAC is definitely bad and need to be replaced."
When I started my jeep it idled at around 600, when I put it into gear the rpms dropped, when I turned the ac on the rpms dropped a little, and when I turned the steering wheel the rpms dropped a little more. Now I am guessing it is the iac. Is there any other way to tell if the iac is bad other than that, what is the genral price of this part, and where exactly is it located?>

[maximumquake]

I am sorry I was wrong my mechanic buddy told me it was the tps. This is the the thing, my jeep will act like it says in the posted(try this to determine if the IAC is bad, start engine, place in gear (drive, Reverse), turn A/C on, and operate the power steering pump (turn wheel slightly right or left). the rpms should increase slightly or remain steady, if it drops or stumbles then the IAC is definitely bad and need to be replaced) only if the motor is warmed up. If I let me jeep sit for a couple hours; it will only act like that after the motor has warmed up. I unplugged the Iac(I believe it is the iac it might be the tps though probably the iac) before it warmed up it ran like shit;as soon as I plugged it back in it ran perfect. But as soon as the motor warmed up; it doesnt matter if it was unpluged or pluged in it still ran the same with the rough idle. My question is if a iac is bad will it work till the motor warms up then give out or will a tps work fine until a motor warms up then it will give out?

[Bob D.]

Sounds more like the IAC. I've never heard of a TPS or IAC quit working when warm but I suppose it's possible.
Have you checked for fault codes?

[Scrapper]

the tps makes it idle high then low when it's working after warming up.iac about does same thing. take your pick.......lol...

[legalfee]

Could also be the ignition coil.

[maximumquake]

yes I have checked for fault codes the only code I get is 55. So there is no fault codes. I am pretty sure it is the iac, because when I unplug the tps the rpms bounce up and down and the motor stalls. But when I unplug the iac it really does not make a difference.

[Scrapper]

your are right on iac go for it because i'll be wrong right along with you because you unplug that it sure should make a hell of a diffirence.

[msdz]

I have replaced the IAc a few times in my JGC and when I have unplugged mine on even the new ones it has never made a difference in the way it ran, hot or cold. On my mother-in-laws Cherokee it causes her Jeep to have an extrememly high idle. So I am not sure what the deal is with my JGC, sure they should have some effect? If so then I am either getting bad IAC motors or have some issues wit the wiring somewhere. I know I have problems with surging while driving now as well and idle surge, sometimes it makes me think it is going to completely die out in traffic. I am starting to get leary of my wife driving it.
Oh, I have replaced all sensors except for the crank, camshaft, MAP and air charge temperature sensor and it still does this. I was told that if engine dies while the MAP is unplugged then it is OK, as for the air temperature charge sensor I have no clue if it will do anything when unplugged and running. Maybe somebody else does, I will try it tomorrow to find out if it makes a difference.
I know I need a new O2 sensor now as well, I just replaced mine about 2 or 3 weeks ago and the same code pops up again after it being off for about a week, code 52. That same code appeared right before replacing the O2 sensor, I cleared all codes after installling the new O2 sensor and it popped up again.
So many things I have done and still this GC runs like crap and I have some projects planned for it soon too but getting it to run right is the main priority.

[Scrapper]

pop's up 0-2 sensor your sure you don't have two 0-2's? then if you haven't sprayed inside throttle body ceaner? only then next module would be my guess. because sometimes it never throad a code just found that i thought coils on a 2.3 no it wasn't it was module. have you looked under hood in the dark to see if can see any sparking on motor anywhere?

[cmsch180]

have the torque converter checked out, my jeep had the same problem and turns out that's what it was, it was trying to engage while the jeep wasn't moving.
just a suggestion.

[acuhealth]

My 95 JGC 5.2L V8 has been having idle problems and stalling. I changed the IAC or ICV , the fuel filter, the PCV, the O2 sensor and I cleaned the intake manifold and throttle body. I still have problems. I believe it may be due to a leak in the intake manifold gaskets. On justanswers.com, an experienced technician told me this is common especially on big engines like mine. The leak confuses the computer which causes the car to act the way it does.

I will be changing the gaskets tomorrow.

[legalfee]

Originally Posted by acuhealth

My 95 JGC 5.2L V8 has been having idle problems and stalling. I changed the IAC or ICV , the fuel filter, the PCV, the O2 sensor and I cleaned the intake manifold and throttle body. I still have problems. I believe it may be due to a leak in the intake manifold gaskets. On justanswers.com, an experienced technician told me this is common especially on big engines like mine. The leak confuses the computer which causes the car to act the way it does.

I will be changing the gaskets tomorrow.

I've had three things cause idle problems on my 96 5.2. The first time it was a dead cell in the battery. Even though the battery passed a load test the car would die at idle. New diehard fixed it. The second time it was an IAC. Put in a new one and it helped. The third time it was a bad ignition coil. Someone here posted it could be a problem and I said why not they're not that expensive. It cured the idle problem. I would try a new ignition coil if you haven't yet. Get a OEM though. The one I got from Auto Zone lasted about a year and left me stranded.