I hate to do this but as I cannot find any info where it seems anyone has had a similar problem...I posted on performance trucks with no help however I have a 2004 Silverado started out as a 4.3 5 Speed truck I scored a 4.8 out of a 2000 with low miles for cheap and also came with the harness from the 2000 maybe someone can help me out with a few problems i've ran into. We currently have it in the truck and all hooked up every ground and every plug minus a couple that go to the transmission because apparently this harness out of the 2000 is out of an automatic is it possible to use this harness or will I need a different one? As of right now none of my gauges are working in the truck and when you turn the key on and try to start the truck as soon as you engage the clutch without even turning the key it tries to start itself however it is not getting fuel and will not start. Hopefully someone can guide me in the right direction here in what i'm doing wrong or what I need to change. Everything off the 2000 harness seemed to plug into eveything on my 2004. Are the fuse blocks different is why i'm receiving these problems or do I need to get a newer style harness? I want to retain the cable style throttle body as the truck was drive by cable is why i've refrained from picking up a newer style harness. Ive read the nbs v6-v8 threads over and over trying to get a solution. Also I forgot to mention the pcm has already been flashed for the 4.8 and mods by nelson performance so once i can work out all the small problems it should be good to go.