2006 GMC envoy
2 Answers
Pull the code(s) and read them to see what could be the problem.
Mary, you shouldn't drive it when it's flashing. More than likely one of your 6 (assuming you have the common I6 engine) coils has failed. Bring it to an automotive store and have them read the codes for you. You should see a P0300 or P0301 thru P0306 which should pinpoint which coil it is IF indeed it's not a P0300 which is multiple cylinder misfire.