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Are you under warranty?
Here is some information on a bulletin they need to look at. This information is avaible to any dealership and the last time you were there they should have performed this repair which is to replace the valve covers.
#12-06-01-001: Service Engine Soon Light On, Rough Running Engine, Cracked or Oil Fouled #1 and/or 7 Spark Plug - (Jan 18, 2012)
Some customers may comment on a service engine soon light being on and/or rough running engine. Technicians may find DTC P0300 set. Upon further investigation, technicians may find cylinder #1 and #7 spark plugs oil fouled and/or the porcelain may be cracked or broken on the combustion chamber side.
This occurs on the driver's side (left side) of the engine due to PCV pullover that adds additional oil to the cylinders that can foul out or damage the spark plugs.
Install a new left valve cover with the revised baffle to prevent PCV pullover that adds additional oil to the cylinders.
12570427COVER ASM-VLV RKR ARM (2007-2008 Only) 12642655 COVER ASM-VLV RKR ARM (2009-2011 Only) 12612045GASKET, VLV RKR ARM CVR
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