# 2007 GMC Yukon - Idles rough - Backfires

**URL:** <https://community.cartalk.com/t/2007-gmc-yukon-idles-rough-backfires/178274>\
**Category:** Maintenance/Repairs\
**Tags:** gmc\
**Created:** [July 26, 2021, 7:14pm UTC](https://community.cartalk.com/t/2007-gmc-yukon-idles-rough-backfires/178274 "2021-07-26T19:14:28Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Mechanic31](https://avatars.discourse-cdn.com/v4/letter/m/dec6dc/32.png) [@Mechanic31](https://community.cartalk.com/u/Mechanic31)\
**Post date:** [July 26, 2021, 7:14pm UTC](https://community.cartalk.com/t/2007-gmc-yukon-idles-rough-backfires/178274/1 "2021-07-26T19:14:28Z")

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Engine idles rough and backfires

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**Author:** ![fleetmanager](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/fleetmanager/32/24111_2.png) [@fleetmanager](https://community.cartalk.com/u/fleetmanager)\
**Post date:** [July 26, 2021, 7:22pm UTC](https://community.cartalk.com/t/2007-gmc-yukon-idles-rough-backfires/178274/2 "2021-07-26T19:22:54Z")

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Any codes? Do you have a scan tool?

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**Author:** ![davepsinbox\_157004](https://avatars.discourse-cdn.com/v4/letter/d/73ab20/32.png) [@davepsinbox\_157004](https://community.cartalk.com/u/davepsinbox_157004)\
**Post date:** [July 26, 2021, 10:11pm UTC](https://community.cartalk.com/t/2007-gmc-yukon-idles-rough-backfires/178274/3 "2021-07-26T22:11:48Z")

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It sounds like a timing problem, possibly a bad crankshaft position sensor.

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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 30, 2021, 12:19am UTC](https://community.cartalk.com/t/2007-gmc-yukon-idles-rough-backfires/178274/4 "2021-07-30T00:19:38Z")

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The timing chain might have shifted a cog, or stretched and there’s too much play between the crankshaft and the camshaft. Suggest to first however verify the routine maintenance is up to date, spark plugs are ok, all diagnostic codes have been read out, etc. It may just be misfiring for example, due to a bad spark plug, coil pack, etc. In any event , to protect your $$$$, this is something that requires fixing w/due speed b/c it could be damaging the catalytic converter.