# Rough running engine when warm

**URL:** <https://community.cartalk.com/t/rough-running-engine-when-warm/50670>\
**Category:** Maintenance/Repairs\
**Tags:** van, chevrolet, rough\
**Created:** [June 21, 2010, 6:46pm UTC](https://community.cartalk.com/t/rough-running-engine-when-warm/50670 "2010-06-21T18:46:54Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![bilbaker](https://avatars.discourse-cdn.com/v4/letter/b/df788c/32.png) [@bilbaker](https://community.cartalk.com/u/bilbaker)\
**Post date:** [June 21, 2010, 6:46pm UTC](https://community.cartalk.com/t/rough-running-engine-when-warm/50670/1 "2010-06-21T18:46:54Z")

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I have a Chevy P30 (basically an old bread van) which started running very rough yesterday on my way home. Out of curiousity I ran it again this morning and it ran fine until it warmed up. What would cause this? I suspect there is a simple solution, like a broken vacuum line etc, but if anyone has a clear idea I would appreciate any info…Thanks

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**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\
**Post date:** [June 21, 2010, 7:22pm UTC](https://community.cartalk.com/t/rough-running-engine-when-warm/50670/2 "2010-06-21T19:22:08Z")

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In general any basic maintenance items could be involved - spark plugs, wires, filters.

Other than that, for a warm only problem I would first check the coolant temperature sensor.

What year is it?

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**Author:** ![bilbaker](https://avatars.discourse-cdn.com/v4/letter/b/df788c/32.png) [@bilbaker](https://community.cartalk.com/u/bilbaker)\
**Post date:** [June 21, 2010, 11:43pm UTC](https://community.cartalk.com/t/rough-running-engine-when-warm/50670/3 "2010-06-21T23:43:40Z")

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Thanks for the suggestions. I’ll check plugs, wires filters etc…It is a 1995. This was not a gradual shift…It went from running fine to very rough basically instantly.

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**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\
**Post date:** [June 22, 2010, 12:33am UTC](https://community.cartalk.com/t/rough-running-engine-when-warm/50670/4 "2010-06-22T00:33:09Z")

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Check the coolant temp sensor - if the computer doesn’t register the van getting to full operating temperature it will continue to feed it a rich mixture - sort of like leaving the choke on after an engine is warmed up.