# Mercedes-Benz idle problem, help

**URL:** <https://community.cartalk.com/t/mercedes-benz-idle-problem-help/8102>\
**Category:** Maintenance/Repairs\
**Created:** [December 8, 2007, 5:04am UTC](https://community.cartalk.com/t/mercedes-benz-idle-problem-help/8102 "2007-12-08T05:04:37Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![todd.burmeister](https://avatars.discourse-cdn.com/v4/letter/t/e56c9b/32.png) [@todd.burmeister](https://community.cartalk.com/u/todd.burmeister)\
**Post date:** [December 8, 2007, 5:04am UTC](https://community.cartalk.com/t/mercedes-benz-idle-problem-help/8102/1 "2007-12-08T05:04:37Z")

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I have a 1994 Mercedes that runs just fine when the engine is cold, but when it reaches normal running temp. it surges when ever you come to a complete stop. If you try to accelerate slowly it misses and sputters for about 10 feet and then it picks up and runs just fine. Any suggestions or ideas for what this might be caused by would be appreciated.

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**Author:** ![mr\_josh](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mr_josh/32/3008_2.png) [@mr\_josh](https://community.cartalk.com/u/mr_josh)\
**Post date:** [December 8, 2007, 5:07am UTC](https://community.cartalk.com/t/mercedes-benz-idle-problem-help/8102/2 "2007-12-08T05:07:51Z")

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Any check engine light? If so, any codes produced? Off-hand, I’d suspect a coolant temperature sensor.

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**Author:** ![Craig58](https://avatars.discourse-cdn.com/v4/letter/c/3da27b/32.png) [@Craig58](https://community.cartalk.com/u/Craig58)\
**Post date:** [December 8, 2007, 5:25am UTC](https://community.cartalk.com/t/mercedes-benz-idle-problem-help/8102/3 "2007-12-08T05:25:35Z")

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Also, take a look around for any loose vacuum connections on the engine. Apparently the O2 sensors can cause surging on some of these. Which engine, the 320?

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**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\
**Post date:** [December 8, 2007, 2:48pm UTC](https://community.cartalk.com/t/mercedes-benz-idle-problem-help/8102/4 "2007-12-08T14:48:19Z")

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I’ve seen brake boosters develop a leak when you press the brake, but seal up fine when you release them. Test this out in the driveway. Get it warmed up, then just press on the brake firmly. If the engine surges or sputters, but stops when you release, then it is the brake booster leaking.

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**Author:** ![todd.burmeister](https://avatars.discourse-cdn.com/v4/letter/t/e56c9b/32.png) [@todd.burmeister](https://community.cartalk.com/u/todd.burmeister)\
**Post date:** [December 9, 2007, 5:48am UTC](https://community.cartalk.com/t/mercedes-benz-idle-problem-help/8102/5 "2007-12-09T05:48:02Z")

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Yes this is a 320. I will check the vacuum hoses.

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**Author:** ![todd.burmeister](https://avatars.discourse-cdn.com/v4/letter/t/e56c9b/32.png) [@todd.burmeister](https://community.cartalk.com/u/todd.burmeister)\
**Post date:** [December 9, 2007, 6:00am UTC](https://community.cartalk.com/t/mercedes-benz-idle-problem-help/8102/6 "2007-12-09T06:00:21Z")

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The check engine light is on. I will have to take it in to get the code readings. I will check the coolant temperature sensor. Thanks for the suggestion.