Replaced the headgasket on a 91 integra gs, (which btw, was a nightmare) and I got everything back together--finally got the timing belt and tensioner to cooperate, hooked everything back up, turned on the car, and it barely idles at 100 rpm, jumps between that and 400 rpm, and then the car dies. There is also a rhythmic thumping sound --aka, doesn't sound normal, when you rev it. Any ideas? I don't really want to take everything back apart again...please help!