# 2015 Chevrolet Impala - can’t diagnose after check engine light **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** chevrolet, impala\ **Created:** [August 11, 2018, 4:48pm UTC](https://community.cartalk.com/t/2015-chevrolet-impala-can-t-diagnose-after-check-engine-light/122721 "2018-08-11T16:48:49Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![EdBoardman](https://avatars.discourse-cdn.com/v4/letter/e/67e7ee/32.png) [@EdBoardman](https://community.cartalk.com/u/EdBoardman)\ **Post date:** [August 11, 2018, 4:48pm UTC](https://community.cartalk.com/t/2015-chevrolet-impala-can-t-diagnose-after-check-engine-light/122721/1 "2018-08-11T16:48:49Z")
Car has 18,000 miles on 3.6 L engine. Number 6 plug oil fouled leading to misfire/check engine light. Dealer replaced plug but no diagnosis. Ideas? ---
**Author:** ![Mustangman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/mustangman/32/44130_2.png) [@Mustangman](https://community.cartalk.com/u/Mustangman)\ **Post date:** [August 11, 2018, 6:08pm UTC](https://community.cartalk.com/t/2015-chevrolet-impala-can-t-diagnose-after-check-engine-light/122721/2 "2018-08-11T18:08:14Z")
Yeah, #6 has an oil control problem and your misfire WILL come back! Do a compression test. If #6 comes back low, there has been some ring damage and that is an issue for. If the compression is OK, a valve seal for #6 has likely prematurely failed. either way it is likely Chevy’s problem - check your warranty. At least you got it on record the plug fouled. ---
**Author:** ![EdBoardman](https://avatars.discourse-cdn.com/v4/letter/e/67e7ee/32.png) [@EdBoardman](https://community.cartalk.com/u/EdBoardman)\ **Post date:** [August 11, 2018, 8:49pm UTC](https://community.cartalk.com/t/2015-chevrolet-impala-can-t-diagnose-after-check-engine-light/122721/3 "2018-08-11T20:49:55Z")
Thank you. All that you say makes sense to me and confirms my thoughts.