need help with a truck at work.
 

Hey guys, I work for a company and we have about 5 trucks with the 24 valve engines in them and I'm having a really hard time trying to figure out what wrong with this one.

Came in 2 weeks ago for stalling issue. stalled on the driver and was towed in, Left it in the lot for 2-4 hours running and when you turn it off and try to re start it just cranks.

So this is waht was replaced.

VP44
Lift pump
Cam and Crank sensor
ECM
Engine wiring harness
all relays


I'm stuck and don't know where to go. I cant figure out what's wrong. We dont have access to any manuals or troubleshooting guides and i'm hoping someone on here can point me in the right direction.

Thank you all for you help. :argh: