Hello everybody, I haven't been here for a long time because my CTS has been so good to me and I have been sticking with scheduled maintenance with the same dealer. About 2 weeks ago, it started but won't run so I had to use my back up car to get to work..things at work were hectic which prevented me from taking care of my CTS. I'm on Spring Break this week and had my car towed to Cadillac Dealer thinking it was a battery issue. The service rep said the valves on the engine are carbonated up and will need recasting due to fuel deposits I asked him what caused it he said it is probably the gas I was using. Said I should be using either chevron or mobile. No where in the owners manual said I needed to use certain brands and I am very pissed. Has anybody ever experienced this or it is a BS as many dealers are hurting economically. Please advise. I do have GMPP extended warranty and I wonder will they cover it. Thank you.