First startup in the morning or if it's been sitting for hours my 99 Jeep Cherokee Sport won't stay running unless you have your foot on the gas. It usually takes a minute or two with your foot on the gas a little until it stays running. The check engine light isn't on, in fact the MIL bulb is working and even through 195,000 miles it's never come on. The tune-up has only got about 10,000 miles on it, using all Mopar parts and OEM plugs. I replaced the idle air control valve once, thought I got a bad one, and replaced it again and recleaned the port out and it still does it. I even cleaned the throttle body out and it wasn't all that bad. I replaced the PCV elbow with a new one. I checked for vacuum leaks all over the intake, throttle body, intake hose, vacuum hoses, and even valve cover grommets and didn't find anything. Any ideas on what it could be? Anything I could check here at home before I take it to the shop?

your idle air control valve is suck closed. take it out clean it up and reassemble. should cure the problem for a while. my jeep does this at the start of winter too. takes me about 5 minutes to clean and i think a new one is $50.00

I replaced it and cleaned out the ports and it still did it. I also just replaced it again with another new idle air control valve and it still does the same thing.

Check your battery and the charging system,you could have enough volts to start, but the pcm looses memory, and does not know where idle speed is
Thad

Check the O2 sensor.Its not supposed to affect idle.But we had one at work that pretty much did the same thing.No check engine light.Got the scanner on it and the voltages were off when cold.New sensor and it was fine.Rocky

A bad coolant sensor can also give you start up problems.It is the first thing that determines the amount of fuel on a cold engine.

About a year or two ago I replaced the thermostat when I had to change the valve cover gasket and then I noticed later on the temp gauge never got to the halfway point. Even in the hot temperatures with a/c on. I put the correct rating thermostat too. It still works, gas mileage wasn't down enough to notice so I didn't think it was a bad thermostat. Could the temp sensor cause that too?

In 30 years Ive found most coolant sensors go to -40 so the computer thinks the car is super cold and runs rich.Ive replaced hundred and you cant get the info without a scanner.I think I had one in all the years that was showing 260 degrees bad.Now Ive seen bad computers etc show some crazy readings.I had one car that was showing batt voltage at almost 30 volts on the scanner.The charging system itself was only reading 14.2 Volts.Rocky

I'll probably just take it to a shop. I don't have a scanner and don't know what other checks I can do myself. I don't want to start replacing all these sensors because most of them are $25-$40 a piece. I just told a shop what I did and he hasn't looked at it yet, but said it could be a lazy or bad injector not spraying a good pattern. So there could be anything wrong with it. I still need to figure out why only the driver's side power window switch works and none of the other ones plus the speaker in driver's door doesn't have sound. So I'll have him check it all.

I have heard about the switches sticking when they are on "lock" for the drivers side control only....If you hit that lock button like a typewritter key off/on it may un stick it and the others will work if not the master switch is bad. Even though the button moves the switch part stays stuck. My truck has the same issue and it's the "lock" feature that is stuck.
As for the speaker it could the wiring that comes outta the pillar and goes into the door finally cracked from opening and closing so much or just that the speaker went bad I had experienced both...Hope that helps...

the wiring issue can be traced back to a broken wire in the drivers side door pillar. i had to lengthen mine after i found there wasn't enough slack to connect the two wires back together. your speaker problem is the same issue. most likely its a ground wire that is broken.

I took it to a shop that I thought was pretty good at diagnosing. I wanted them to check the idle problem. They had it all day while I was at work. They told me to buy a $60 MAP sensor and then they told me it didn't do anything. The fuel system, all sensors, check for vacuum leaks, and a scan was done and they couldn't find out what was wrong. So now I own a $60 MAP sensor that I didn't even need and it still won't stay running when you start it up unless you give it a little gas for 2 minutes. The guy said maybe youre computer is bad, but thats a $300 maybe for the part. I wasn't there to watch so I don't know how everything was checked. Is there a way to test that TPS sensor and Coolant sensor to verify if they are bad? Is there a way to test the computer?

I know there is some basic diagnosis one can do with a multimeter.
I'd suggest taking the problems to jeepsunlimited.com or naxja.

I did try a couple Jeep forums on this and several prior problems but was ignored. Maybe because I've just got a stock 4x2 Cherokee and wasn't cool enough. I always have more luck here than anywhere else. None of the shops around here know what to do unless the Check Engine Light is on.

Have you done the basic stuff including checking grounds and unplugging electrical connections to sensors and iac then cleaning and reconnecting? Make sure you have a known good battery, check dist cap for moisture, spark plugs, all spark and coil lead inserted all the way and vacuum leaks?
If you have done the above and it persists, I feel it is an issue with the idler air control valve or the passage leading to it may be carboned up.
The iac is the round unit with wires running to it on the side of the throtle body.
If your battery is old and getting tired, it will take some revs for the voltage to alt. throw enough juice to keep the motor running and also give the battery enough juice to maintain (thus it runs after revving for a few). It's common for batteries to begin fail upon the onset of cool damp fall weather.
Have it checked, or swap out with a known good one, even if you simply use another vehicle to jump to yours when it's cold.

I can't remember why, but I don't think it was totally gone. But a years ago we spliced in a new terminal on the negative cable and hadn't had any problems from it. It's clean and doesn't have any corrosion on it. It's a gold plated terminal end. I don't know if the shop I took it to today even checked the battery and charging system but I can do that. The battery is a few years old. At first I thought I got a bad IAC valve because I initially thought that was the problem just like they go out on Fords. But it didn't fix it. So I went back and removed it and cleaned out the passages. I then replaced it again with another new IAC valve and still no change. There is no leaks anywhere for sure of that. No vacuum or oil leaks at all. I like to keep everything dry. I may decide to try a thorough removal and cleaning of the TBI. I might be able to get at the IAC port better with the TBI unit off.

A short length of a bicycle brake cable with a slightly frayed end chucked in a drill will make quick work of cleaning the passage out.