The van will start and run for about 2 seconds and quit i changed fuel pump,filter,distubitor,cam and crank sensors and module

If van starts then quits, could be passlock theft system.reset system to see. ( is the theft system light on! ) if so do this. attempt to start the van, let it stall, but do not turn key off! leave it in run. wait 10 minutes untill the theft light glows steady instead of blinking. do not turn key off, but start it immediatly. this should reset your passlock system. good-day! this works for all gm vehicles.

Gm vehicles have been known to have faulty anti theft security systems. One of the symtoms of this is when your vehicle starts for 1-5 seconds and then stalls. A good way to know if this is the problem is when you see a light on the dash that says SECURITY. If you see this light flashing or on solid, this explains the van not starting. This link might help you

http://vatspasslockpasskeysecurityhelp.yolasite.com/