OK, it's been a while (I hate it when life gets in the way ;-) but I finally got everything together and fired up.. Well almost..
The car will fire and run for a few seconds and then die-
It almost acts like it's not getting enough fuel (40# injectors @ 58 PSI- Plenty of fuel for this engine).
I've got good spark (lights right up and runs smoothly for the few seconds it does run) but I don't know how to tell if the distributor is perfectly set since this is an aftermarket intake and the Vortec distributor doesn't allow for adjustment without modifying the clamp.

Now for the fun part, how do I troubleshoot something that only runs for a few seconds?
Are there any logs I can pull from the PCM to help point me in the right direction?
I started off with a 2002 L31 Express Van tune and modified it accordingly.
Sorry if this is a really basic question but I'm just trying to determine where to start with troubleshooting 101-
Any advice would be most appreciated.
Thank you!
Elm