[S.J.SLEEPER]

Really simple to diagnose... Think of the 4 major elements you need to run:
Air
Fuel
Spark
Compression

getting air into intake via air intake housing? yes does fire up & run

Getting spark? yes does fire up & run

Compression? yes does fire up & run

Getting Fuel? only when force fed....

diagnose:
check for fuel pressure when key turned to start position: should be 40psi +
no???
check for 12v+ @ fuel pump
no???
check fuel pump fuses, & relay for voltage & so on...

If you Have voltage @ pump, then make sure pump is turning on, if not then replace pump

Have fuel pressure....yes????
Then install noid light on injector plug, crank engine,while cranking, look to see if you have injector pulse.

Have injector pulse....No???
Then check inj fuse, check all harness connections, etc..
If you have Injector pulse, then may be a timing,opti, or ecm problem

Don't overlook the obvious.... it could be as simple as a fuel filter being completely plugged up!!!