Starts up fine when cold, stalls when hot

2000 MITSUBISHI GALANT
63,000 MILES • 6 CYL • FWD • AUTOMATIC
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DAVID SR.
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I received a service engine light and scanned an error code describing downstream o2 sensor on rear head. I disconnected the negative side of the battery has instructed in the manual and then proceeded to remove the 02 sensor on the muffler side of the catalytic converter. Not much room to work with but success.

I then proceeded to change the oil while I had the car jacked up along with the oil filter, no issues.

Then I reconnected the neg side of battery and started up the car. Car started up just fine and no more service engine light. I let it run for a few minutes to warm up and then turned the engine off.

I had the car parked near the garage door and needed to close the door. I jumped in the car and the car started up and then died. Subsequent startups are the same has long as the engine is warm. If I wait for about 20 minutes it will start up and run like normal until it gets warm again.

Also please note there is no service engine light at this time.
Dec 9, 2008 at 10:59 PM
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RACEFAN966
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Ok so when it dies do you loose spark or fuel? Have you checked either when it dies to see which is missing? Thanks and get back to me and let me know what is going on.
Dec 9, 2008 at 11:41 PM
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DAVID SR.
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spark and fule is good.........if I give it a little gas after the restart when the engine is warm I can keep it running by stepping on the gas to keep up the RPMs. Its when i take my foot off the accelerator it dies. Seems to be an idle issue.

I read somewhere maybe in Carpros forum or another info website that if I disconnect the battery again and just let it idle without accelerating or going through the gears the computer will reset the idle as it goes through the warm up cycle.

Well believe it or not when I got home I disconnected the neg. side of the battery and let the car sit for about 10 minutes .
Then I reconnected the battery and restarted the car without touching the accelerator and just let it warm up. I let it run/warm up for about 20 minutes,turned off the car and attempted to restart with success. i did it again, and again no problems.

I will keep you posted over the next couple of days to be sure and determine its not a fluke.
Dec 11, 2008 at 12:34 AM
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RACEFAN966
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This sounds like the engine coolant temperature sensor is not working right Here is a guide to help you see what you are in for when doing the job.

https://www.2carpros.com/articles/coolant-temperature-sensor-cts-replacement

Here is the location for your car (below)

Please let us know what happens.

Cheers
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Dec 11, 2008 at 10:03 AM
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DAVID SR.
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Wow that fixed it, so good thanks for your help I didn't think that would do it but all good now :)
Dec 11, 2008 at 11:48 PM
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RACEFAN966
  • CAR REPAIR CONTRIBUTOR
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Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help. Thanks again and have a great Christmas and Happy new year.
Dec 12, 2008 at 9:53 AM
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