Misfiring

did you check compression?

I have not checked compression

It's got 106000 on it. Plugs were all replaced a few months ago. I put a new plug in cylinder 2 and switched coils between cylinder 2 and cylinder 4. Put it all back together and the same codes and symptoms. Oil changes have been done every 3000 miles. I never trusted the oil life calculator. As far as the sport button.... I've played with it from time to time. That is until the transmission cooling line blew off the radiator. Quite the mess with that one. Its been labeled the self destruct button. The cars been taken care of. Normal wear and tear. It's thrown it's temper tantrums. New computer about a year ago. Just need her back on the road.

I've had the battery unhooked multiple times. That's pretty much it.

That's a problem with ECM

Did u find out why it was misfiring cause my 05 srx is doing the same thing but it's on cylinder 6

I have a 2005 CTS and I replaced two new spark plugs and two new coils because it said cylinders 1 and 2 for misfiring installed them and crank the car back up and it was running 10 times worse plug the computer back up to it and now it says all the other cylinders are misfiring and fuel injectors and all type of codes went from about 2 or 3 codes to about 15 codes I'm at a loss .

I had similar issues with 05 CTS and Cadillac determined it was bad injector coil. Cost me around $700 but dealership treated me better than any shop has ever.

When i bought my CTS 2005(2004 in europe) i had the same problem did some procedure changed all the plugs and coils where it read it had a misfire. Its also a V6 3.6L eng i think these engines are just not that good now i think mine doesn't have much left but all you can you do is change the plugs every now and then and make sure it has enough oil. Today i have misfire in eng 1,5,6 turns out nr 6 was really f****** the socket on the coil that goes over the spark plug was stuck to the plug and the plug it self was also burned out. nr 5 coil is good but the plug is bad and i haven't started on nr 1 yet but i'll have to take the ENG valve of to get to it and most the others which is the biggest pain in the a**.

Once you change coils you must replace oil too. I have the 2007. You also should just change every coil because if not they all start to go shortly after. It’s almost like your head gasket is going but it’s the coil packs plus a tune up is great after.

I had similar problem but it was the fuel injectors were going bad causing plugs to go bad then a misfire

Just had 3 coils and oil change in my 05. Haven't picked it up yet from my mechanic, but here's hoping all is fine.

have a 2006 cts 2.8 , had a reading of a misfire in all cylinders 1,2,3,4,5,6, my car sit all winter, i just start once every two weeks , i figure that the gas was getting old so what i did is bought the better gas and put it in the tank, i erased the codes , that fixed my problem , check engine light never came back on after that.