Did you check for spark on all plugs? If fuel pressure is good at the rail and you are getting good spark at all cylinders, then I don't know. Timing? ECU? It would seem something is telling the spark to spark at the wrong time.
This may sound stupid, but maybe your air intake is clogged? Fuel and spark mean nothin without air. Or another far out idea, if the cat was 100% clogged it couldnt run then either, but thats pretty unlikely.
Hmmmm. . . :hmm: