Ok so i know its the #5 glow plug. Does any body know how to test and replace the GP?

I know GM recommends to replace all 8 but since this is not under warranty is there really a need?

Is there a good manual out there that I can download? A while ago the was a manual on here for the electrical system and it was great, jus need one for the mechanical systems.

Thanks for the Help
Josh

Much like replacing spark plugs (and in about the same place):
Remove:
Disconnect the negative battery cable.
Remove the left (or right depending on which side you need) wheelhouse panel.
Remove the engine wiring harness nut(s) from the glow plug(s).
Remove the engine wiring harness lead(s) from the glow plug(s).
Remove the glow plug(s) from the cylinder head.Install:
Install the glow plug(s) to the cylinder head. Tighten the plug to 18 N.m (13 lb ft).
Install the engine wiring harness lead(s) to the glow plug(s).
Install the engine wiring harness nut(s) to the glow plug(s). Tighten the nut to 1.7 N.m (15 lb in).
Install the wheelhouse panel.
Connect the negative battery cable.I've never done it my self, but looks to be pretty simple.

thanks Ron!! Is there somewhere I can find out what cylinder is #5?

#1 is front cylinder on Right, passenger bank, and the others, front to back on the right side are 3,5,7. Drivers side, front to back, are 2,4,6,8. This per Alldata DIY.

That's different than most conventional Chevy engines. As a general rule, the #1 cylinder is the frontmost cylinder on the engine.

Firing order:
1-2-7-8-4-5-6-3

Thanks Ron!