cranks but won't start?

Here is OEM service manual info :

ENGINE START-UP MODE

This is an Open Loop mode. The following actions occur when the starter motor is engaged.

The PCM receives inputs from:
•Battery voltage
•Engine coolant temperature sensor
•Crankshaft position sensor
•Intake manifold air temperature sensor
•Manifold absolute pressure (MAP) sensor
•Throttle position sensor (TPS)
•Starter motor relay
•Camshaft position sensor signal

The PCM monitors the crankshaft position sensor. If the PCM does not receive a crankshaft position sensor signal within 3 seconds of cranking the engine, it will shut down the fuel injection system.

The fuel pump is activated by the PCM through the fuel pump relay.

Voltage is applied to the fuel injectors with the ASD relay via the PCM. The PCM will then control the injection sequence and injector pulse width by turning the ground circuit to each individual injector on and off.

The PCM determines the proper ignition timing according to input received from the crankshaft position sensor
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This is a very unusual problem , usually the most common thing is to lose spark and the injection signal together and it usually is due to a loss of crank signal , very common problem on these.
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If you are loosing injector pulse with your ignition switch in crank position I would be checking power to the pcm with the ignition switch held in that position. There is power that should be hot in crank and run position. I would check both the powers and grounds here at the pcm .

Best way to check powers and grounds at the computer is to use a sealed beam headlamp ,it puts that circuit under load.
Get you a headlight with a couple of leads, ground one lead to the battery negative and use a straight pin or paper clip on the other lead and insert it into the pcm connector on your powers ( connector 1 pin 2 and pin 22 are powers ) look for a nice brightly lit headlamp and make sure it has power in run and crank on pin 2 cavity.
Reverse to check your grounds , one lead on the positive battery and the other checking the connector pins 31 and 32 . These are the two grounds ,once again looking for a brightly lit headlamp which tells you its a good ground under load.
These powers and grounds have to be good for everything to work.
The pcm controls the charging system , so the grounds have to be right to work .