For the past few months my check engine light has been on and i scanned the car and two trouble codes have came up. the codes are:
P1406(which is a EGR Valve problem) and P303( which is cylindar 3 misfire). And With the Cylindar 3 misfire, The Camaro has new plugs that are tight, New Coil Pack the only thing that isnt new is the wires. Im assuming i need new wires. I replaced the EGR Valve with a brand new one and the wires and all going to the EGR Valve are fine. So What Possibly could the problem be? And could the camaro's rough idle result from the misfire or the EGR Valve problem? Please Help me, Im loosing about 10 mpg's due to these problems.

 

Fix cylinder 3 and you mileage will go up, and probably resolve the EGR code also. Cause of misfire, the usual 3 causes: Ignition (Plugs, wires, coils, ignition module, Fuel problem (Bad injector, bad wiring to injector), mechanical problem which is killing compression (bad valves, worn out cam lobes, broken piston, blown head gasket, etc..)