My 04' GTO has the engine light on and its reading Banks 1 and 2 are Rich. I have changed the Throttle Body on it to a 90mm, MSD 8.5 wires w/NGK TR55 Plugs, Custom Exhaust(no cats), K&N Cold Air Intake and a Tune on the car(twice) and both times after about 10-15 miles the engine light came back on. Does anyone have any ideas on whats going on and how bad is it to drive around in it w/the Banks to Rich because I raced a Mach 1 Mustang w/the engine light on and beat it so it doesnt seem to be affecting the car that i can tell.

Where did you get it tuned?