# Saturn idle issues

**URL:** <https://community.cartalk.com/t/saturn-idle-issues/80590>\
**Category:** Maintenance/Repairs\
**Tags:** saturn\
**Created:** [July 27, 2013, 11:11pm UTC](https://community.cartalk.com/t/saturn-idle-issues/80590 "2013-07-27T23:11:01Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![JennS2013](https://avatars.discourse-cdn.com/v4/letter/j/48db29/32.png) [@JennS2013](https://community.cartalk.com/u/JennS2013)\
**Post date:** [July 27, 2013, 11:11pm UTC](https://community.cartalk.com/t/saturn-idle-issues/80590/1 "2013-07-27T23:11:01Z")

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We have a 1997 Saturn. For the past few months, whenever we’re at a stoplight it suddenly fluctuates in RPMs, giving it a rough idle (going from 1000 down to 500 or so for a second or two, before coming back up to normal). It appears to be temperature sensitive (i.e. the longer the car runs or the hotter the outside temp, the more often this occurs). I sprayed the throttle body connection and vacuum connections to attempt to find a potential vacuum leak, with no effect.

We’ve already had the transmission replaced, and haven’t been having any other idle issues besides this. Any ideas of what else might be causing it?

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**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\
**Post date:** [July 27, 2013, 11:58pm UTC](https://community.cartalk.com/t/saturn-idle-issues/80590/2 "2013-07-27T23:58:03Z")

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Anytime a vehicle has an idle issue the first thing to suspect is problem with the Idle Air Control valve. [http://www.rockauto.com/catalog/moreinfo.php?pk=1006310&cc=1266847](http://www.rockauto.com/catalog/moreinfo.php?pk=1006310&cc=1266847)

As these are just stepper motors they can be effected by heat and start hunting for the proper idle position.

Tester

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**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\
**Post date:** [July 28, 2013, 4:40am UTC](https://community.cartalk.com/t/saturn-idle-issues/80590/3 "2013-07-28T04:40:32Z")

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I always suspect a vacuum leak first on this symptom. Has the intake manifold vacuum at idle been measured? On most cars, it should be around 20. It is possible the leak could be in something where spraying it wouldn’t be diagnostic, like if the brake booster diaphram sprung a vacuum leak. Ask your mechanic to check for diaphragm leaks on all of the vacuum operated devices, including the brake booster and the fuel pressure regulator.

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**Author:** ![JennS2013](https://avatars.discourse-cdn.com/v4/letter/j/48db29/32.png) [@JennS2013](https://community.cartalk.com/u/JennS2013)\
**Post date:** [July 28, 2013, 6:54am UTC](https://community.cartalk.com/t/saturn-idle-issues/80590/4 "2013-07-28T06:54:08Z")

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Worked perfectly! Changed/ cleaned the IAC and the problem’s gone! Thanks!

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**Author:** ![George\_San\_Jose1](https://avatars.discourse-cdn.com/v4/letter/g/e5b9ba/32.png) [@George\_San\_Jose1](https://community.cartalk.com/u/George_San_Jose1)\
**Post date:** [July 29, 2013, 3:11am UTC](https://community.cartalk.com/t/saturn-idle-issues/80590/5 "2013-07-29T03:11:20Z")

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Good for you JennS2013 to get your car working like new again, and good on @Tester for the great advice.