Leaky Valve Cover?
Owners of 2012-2013 Chevy Tahoe vehicles may note a service engine soon light, a rough running engine, and/or oil consumption. Technicians may find DTC P0300 set.
If this is encountered, inspect number 1 and 7 spark plugs for oil fouling, as well as the intake manifold runners for excessive oil. This can indicate oil pullover from the PCV system.
Clean the oil from the intake and the PCV baffle. Check for possible PCV baffle leaks with the left valve cover removed. Check for possible PCV baffle leaks by plugging both of the baffles’ small hole and square vent, then apply regulated air pressure through the PCV pipe and spray soapy water where the PCV baffle and valve cover meet to inspect for possible signs of a leak.
If a leak is found, the valve cover should be replaced. The new valve cover should also be tested prior to installation.