420A Crank no start

[Basic2g]

I have a 1996 turbo 420a eclipse and I recently put a new transmission in it I drove it for a couple days after then one day I go to start it and it doesn’t want to stay started it cranks fires and dies so I checked for vacuum leaks there were none then replaced both sensors on the throttle body figuring that would do it I go to start it and it runs just like new again so I turn it off after a test drive. I come out a little later and try to start it to go to the store and it just cranks no fire I have 4 day old spark plugs in it and a brand new coil pack so I know I have spark I also have enough fuel because my pressure gauges are reading right. I am just stumped now