All fuel pressure readings are taken with the engine off, not cranking. Low voltage, or poor ground to the fuel pump will cause fuel pressure to drop. Take all 4 readings as explained in post #1, post them in a new thread, and we will help you diagnose the problem.

 

Thanks Hook! Great write up. It'll save me a lot of time and money and it's such a simple test.

 

Would you only use the GM AC Spider injector or would say GB Rebuild for 1/3 of the cost work just as well?

 

I would definitely avoid rebuilt, reconditioned, and remanufactured units. If you have a 1996 or newer, go with the upgraded assembly. AC Delco 217-3028, Delphi FJ10565 and BWD 63885, are all good choices. Check Amazon, Ebay, and other online sources for the best pricing.

 

Okay thanks . Mine is a 95.. Other good ones?I've seen this link.
Poor Mans Repair Guide For Chevy,GMC Vortec Fuel Injector spider or CSFI System

 

The link refers to 1996-2005 CSFI systems. They are equipped with 6 injectors, 6 spider lines, and 6 poppet nozzles. Your 1995, (more than likely) has CMFI, which uses only one injector with 6 spider lines and poppet nozzles. The two systems are not interchangeable. Repairing your CMFI injector assembly by replacing the injector, fuel pressure regulator, or individual spider lines, is not cost effective. Stay away from used, rebuilt, or remanufactured units, they're likely to have the same problem you're trying to fix.

 

http://www.summitracing.com/parts/ad...er?prefilter=1 this a good one?

 

There ya go! That's it. Don't forget to replace the plenum gasket, the lines, (commonly called "nut kit"), and the electrical connector for the injector.

 

That sir was one of the most beautiful things that I have ever read!
Thanks!!

 

Thanks for supplying the information left out of the *insert favorite phrase here* Hayne's manual... we've spent over an hour looking for the 'fuel pump test plug'... and after another hour searching online stumbled onto your great post & find out that it's located as a plug port inside the fuse box on newer models!

Thanks again!