# Fast idle

**URL:** <https://community.cartalk.com/t/fast-idle/76423>\
**Category:** Maintenance/Repairs\
**Tags:** volvo, 240\
**Created:** [December 31, 2012, 1:52am UTC](https://community.cartalk.com/t/fast-idle/76423 "2012-12-31T01:52:44Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![okjohn](https://avatars.discourse-cdn.com/v4/letter/o/6a8cbe/32.png) [@okjohn](https://community.cartalk.com/u/okjohn)\
**Post date:** [December 31, 2012, 1:52am UTC](https://community.cartalk.com/t/fast-idle/76423/1 "2012-12-31T01:52:44Z")

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car has begun to idle very fast ( comes and goes ) ( 1992 240 )

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**Author:** ![SteveF](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/stevef/32/2_2.png) [@SteveF](https://community.cartalk.com/u/SteveF)\
**Post date:** [December 31, 2012, 2:48am UTC](https://community.cartalk.com/t/fast-idle/76423/2 "2012-12-31T02:48:14Z")

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Possibly a faulty coolant temperature sender. Computer thinks the engine needs to warm up. Can you replace it yourself?

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**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\
**Post date:** [December 31, 2012, 2:51am UTC](https://community.cartalk.com/t/fast-idle/76423/3 "2012-12-31T02:51:04Z")

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Dirty throttle body  
Faulty idle air control valve  
Vacuum leaks

Open the hood and listen for any obvious vacuum leaks (hissing) at idle  
Clean the throttle body  
Tap on the idle air control valve. If the idle changes, the IAC is faulty.