We did pressure test with fuel gauge and determined it was the spider assembly. There was another very helpful post (or maybe it was another site, sorry this was 1 1/2 yrs ago) that showed what the pressure should be - ignition turned (but not started) and what pressure did after this (held pressure or not), pressure when started, etc. It was narrowing down what could be causing the problem is pressure responding accordingly.
Sorry I don't know where this post is, but the experts in here had answered someone else problem and it worked perfect for us. Do as jCat said and use the fuel pressure gauge.
I just remembered and found these two links that I was using to find my problem. Hopefully these might help.
http://troubleshootmyvehicle.com/gm/...uel-injector-1
- this site also has fuel pressure testing that could take you down another path other than spider assembly. If you do a little poking around you should be able to find testing pressures and if XX pressure then proceed with these tests and if another pressure then go down this path.
http://www.justanswer.com/chevy/0b4c...s-battery.html
Good Luck!