I just bought a 1998 Grand Prix 3.8 NA, it has 177,000 miles. Guy I bought it from said he shut it off to fill with gas and went to restart it and it wouldn't start. He had a friend from that town come help him. That friend said that station sold crappy gas so they went and put 5 gallons of gas from another station in it and a couple bottles of heet and injector cleaner. He said they cranked it over and it let out a puff of white smoke. He took it to a mechanic friend of his and he was told it had a blown head gasket.
I just got it home late tonight and looked at it a little. No foam on oil fill cap. Oil on dip stick is clean and not over full. Intake gaskets are leaking externally. Engine turns over fine and acts like its trying to fire on a couple cylinders. I did give it a sniff of ether and it didn't fire, I'm guessing plugs are fouled now. I've heard stories about 3.8 intake gaskets but never had any experience with them. I've been a diesel mechanic for 20 years so I know my way around engines. Just looking for help from guys that have had this problem, I'm wanting to keep this car total low budget for a work car.