My son drove it home, everything normal, left with friends on a road trip in another car for 6 days, got back and crank, no start. I looked at it, used a scan tool, no codes. Holding down the gas pedal it catches a little bit, almost starts, but doesn't. Looking in the forms, I found one single post that seems to indicate the timing chain skipping a tooth. I'm looking for any information I can get. TIA