99 Cherokee sport 4.0L won't idle in the morning
#823207
10/06/10 12:51 AM
10/06/10 12:51 AM
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Joined: Sep 2009
Posts: 153 Georgia
wh23g3g
OP
member
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OP
member
Joined: Sep 2009
Posts: 153
Georgia
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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?
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Re: 99 Cherokee sport 4.0L won't idle in the morning
[Re: olemopar]
#823211
10/07/10 11:15 AM
10/07/10 11:15 AM
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Joined: Jan 2003
Posts: 21,079 Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,079
Niles , Ohio
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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
Chrysler Firepower
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Re: 99 Cherokee sport 4.0L won't idle in the morning
[Re: wh23g3g]
#823214
10/08/10 12:12 AM
10/08/10 12:12 AM
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Joined: Jan 2003
Posts: 9,436 Blair County,PA
62maxwgn
master
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master
Joined: Jan 2003
Posts: 9,436
Blair County,PA
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Quote:
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?
Coolant sensor and temp sensor are two different pieces.Temp sensor could cause the gauge to read wrong,coolant sensor has nothing to do with gauge.
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Re: 99 Cherokee sport 4.0L won't idle in the morning
[Re: None2Slow]
#823216
10/08/10 11:09 AM
10/08/10 11:09 AM
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Joined: Jan 2003
Posts: 21,079 Niles , Ohio
therocks
oh wait.but hey.lets see.oh yeah.
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oh wait.but hey.lets see.oh yeah.
Joined: Jan 2003
Posts: 21,079
Niles , Ohio
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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
Chrysler Firepower
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Re: 99 Cherokee sport 4.0L won't idle in the morning
[Re: wh23g3g]
#823218
10/09/10 10:01 AM
10/09/10 10:01 AM
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Joined: Jul 2003
Posts: 6,343 SE PA.
QuickBpBp
master
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master
Joined: Jul 2003
Posts: 6,343
SE PA.
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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...
Last edited by QuickBpBp; 10/09/10 10:02 AM.
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Re: 99 Cherokee sport 4.0L won't idle in the morning
[Re: wh23g3g]
#823223
10/12/10 02:08 AM
10/12/10 02:08 AM
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Joined: Jan 2003
Posts: 15,802 Jefferson State
srt
ESYC
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ESYC
Joined: Jan 2003
Posts: 15,802
Jefferson State
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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.
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