I have a 2007 Pontiac Grand Prix GT Supercharged it's running sluggish has no power and looses speed on an incline
It was throwing 2 codes, P0404 EGR Valve and P0300 multiple random cylinder miss fire. I have replaced
the plugs and wires, cleaned throttle body, blew an injector out and ran sea foam injector cleaner in it,
cleaned mass air flow sensor, replaced the EGR valve, and the car is still running like crap no power and
loose speed on an incline and still throwing P0300 multiple random cylinder miss fire what do I do next.
HELP :-{ 68k miles on it