I just bought the car and replaced one plug that was cut. This blinking CES light only comes on when i step HARD on the gas pedal, but if im just driving normal in the highway i can go up to 90mph w/out any problem, thats of course if I dont step hard on it.
I will just be taking it to ASE Mechanic and have them check it out. Since i just bought the car at 44,xxx miles and it had delphi plugs, im not sure if they were recently changed but when i carfaxed it it was takin care of, because it was on a maintenance check every now and then.
( Are Delphi the OEM plugs for the '06 grand prix's? )