>On lunch break today my bus stopped running. I noticesd a peculiar
>hesitation when accelerating yesterday. Today it got worse, as if it
>were misfiring or not getting enough gas. I pulled over, checked for
>leaky air hoses, connections, double relay wires, even point gap...still
>nothing. At first it would turn over, run rough a few secs. then die. 
>Then there were two big backfires and now it won't start, just turns over.
>

The condensor on the side of the distributor may have died, or maybe a 
sticking airflap in the air control box. Backfires in FI systems are 
unusual, often caused by air leaking into the exhaust system via rust holes, 
but this is when running. Sounds like you weren't getting a spark for a few 
turns, then it lit up. Has the distributor come loose and let the timing 
drift way off? Good luck, doesn't sound serious, just annoying.  tim s.