Just read through the thread and was wondering if you have a aftermarket ecu? Could be a cold start fueling problem like I was having with my motor as the situations sound very similar.
I changed my rotor arm and spark plugs, with no effect. It would turn over quite well but would never come to life, (it would bump start though).
Took it to the tuner and it ended up being a cold start fueling issue with the map (It had been mapped in the middle of summer so no cold mornings were around).
Have you checked your air filter?