2003 Monte Carlo SS check engine light flashing Pleas Help!

[theungreatone]

Hi. My 2003 MC SS has been acting up, the check engine light starts flashing at me and the car starts shaking when I turn the AC/Heat on. I have no idea what is going on. I know nothing about cars and before I take this to a mechanic, could someone tell me what might be the issue, I do not want to go somewhere and get totally ripped off.

Thanks

[gmtech1]

There is probably a misfire code set, could be a general code, or a cylinder specific code. May be caused by several things. Plugs, wires, coil(s), ect...,with the a/c on, its adding a load and making it worse. Need to have the codes checked.

[theungreatone]

My friend just ran the codes and we got some cruise control codes and a solid misfire on the 5th cylinder but he has no idea what it is. Do you have any ideas for me?

[gmtech1]

Not sure on the cruise codes. With the #5 misfire, could have a bad plug, wire, coil, or even a burned valve in the head (least likley, but possible). Start with the plugs. espically if they have not been replace in a while, you can even swap plug and/or wire to another cylinder and see if the misfire moves. If its been awhile since the pluge and wires were replaced, I would just do that and see what happens.