Rough Idle when Cold - JeepForum.com

 
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post #1 of 4 Old 11-05-2009, 08:31 AM Thread Starter
Titleistprov21
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1999 TJ Wrangler 
 
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Rough Idle when Cold

Hi all,

I'm new the the Jeep community. Just bought a '99 Sahara with 127k miles. Absolutely love it!

I would appreciate any insight into my problem: When it is cold in the morning and I start er up, it has a very rough idle. Jumps from 500rpms to 1500 rpms very quickly and goes up and down like that until she warms up. and after the engine warmed up, my Check Engine light came on. I am going to run the codes today.

Even after the engine warms up, regardless of air temperature, sometimes it will idle at 600rpm, and other times it will idle around 1400rpms, but it doesn't fluctuate like it does when it is cold.

Any thoughts?

Thanks in advance for your help,

-Patrick

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post #2 of 4 Old 11-05-2009, 09:10 AM
OutermostJeep
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Throttle Position Sensor (TPS) ? Do a search for it and see if anyone's symptoms match.
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post #3 of 4 Old 11-05-2009, 10:52 AM
TheBoogieman
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Welcome to Jeep forum.Clean the IAC with a good carb cleaner and you'll be fine.Post # 2 for details.Check the codes though and it will tell you exactly what's wrong.

http://www.jeepforum.com/forum/f9/iac-question-489089/

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Originally Posted by mrblaine View Post
Springs have one job and one job only and it isn't to affect, determine, or create ride quality.
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post #4 of 4 Old 11-05-2009, 10:54 AM
TheBoogieman
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Quote:
Originally Posted by OutermostJeep View Post
Throttle Position Sensor (TPS) ? Do a search for it and see if anyone's symptoms match.
TPS would be the problem if it did it while driving and not just at idle.

Quote:
Originally Posted by mrblaine View Post
Springs have one job and one job only and it isn't to affect, determine, or create ride quality.
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