just this past year the check engine light came on. i had a freind check the obd code for the check engine light and it came up with a p0303. i replaced the spark plugs, the the check engine light turned off a few months past and it came back on again i replaced again all spark plugs with boots. the light went away for a few months, and just the past month it came back on again. im about to change the coil ingition and fuel injector if this continues what else do I have to replace for my engine to run normal so i can get my smog cleared and done.
p0303 i have replaced two of each each fuel pumps and spark plugs. what now? on 2005 Chevrolet Colorado
by robert38 in Indio, CA on November 10, 2011
ANSWER by Jim Taddei on November 10, 2011
You may have a problem with on of the valve seats, this has been reported as a common problem - http://repairpal.com/worn-valve-seats-may-cause-engine-misfire-115. Performing a cylinder leakdown test may be necessary to confirm this.