well i agree with you about the timming chain and that it is unlikely that it jumped and that it would run, althrough i have had acouple engine's run with a chain that has jumped 1 tooth, just very poorly. i was just tring to help him check all the bases thats all. it does sound like an ignition problem, and if he has a cat on the vechile then i would check out the poss of pluged exhaust also jmo.