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.