I recently purchased a 2004 Chevy Silverado 1500. I only paid $250 cash. I tried buying the truck years ago. The truck originally had a 4.8 vortec. The guy swapped it with a 5.3 vortec. He did a body mount on the truck my guess it wouldn’t fit in length he cut the wires then re splitched all the wires. Witch would be why it says reduced engine power when ever I hit the gas pedal nothing. So he then changed the pedal and sensor because it has a drive by wire throttle body. That didn’t work so he then cut the wires to the throttle body. I can see the connector don’t even fit. When I hit the high beams it shuts my truck off and I don’t have half the power to the fuse box. My question is Idk what year motor that 5.3 is I’m pretty positive it’s a 2004 motor but if not how do I find out the year of the motor ? I have been trying to find a complete harness on eBay for the truck interior and engine harness. All I see are painless wiring kits or places that re wire and glacé the pcm. I really wanna have the pcm flashed anyways what would y’all do? I DO NOT WANT TO GO TO A JUNK YARD! I work 15 hour days rather order it and put it on my self.

So I found another 2004 Chevy Silverado. I purchased the under dash harness and the 5.3 engine harness and the 4l60 trans. It does have a drive by wire throttle body. I’m just buying the harness no pcm gonna re use the orginal pcm. Gonna change the location of the ground and buy a new throttle body and pedal and model. Do I have to have the pcm re flashed for vats. Even tho I’m reusing the original pcm.

Also I’m buying a new fuse box for the cab and the engine. Just want to know if ima come across any promblems installing this new harness.

I want to change the grounds because the guy cut every wire to the harness when he did the body lift. He put all the grounds on one side under the cab. It is giving me the reduced engine power. I read on forums if the ground isn’t in a good place the reduce engine will come up. I’m worried that since the body lift wasn’t bolted down right with the cab moving a lil when it runs the ground ain’t gonna be secured right. I rather it be done and me be able to get access to the ground cables to cause I’m gonna take the body lift off and do a air bag lift kit or a shock and coil lift kit I don’t like how he made the body lift he made it him self and it’s all messed up.

Money ain’t a issue I just want the truck to be reliable! I only have 800 into the truck with having it towed buying it and buying both the engine and under dash harness. That’s why I’m buying the throttle position sensor and the throttle body that way I know for a fact everything this moron did is fixed. I work 16 hours a day and only have one day a week to work on the truck. I want to have everything ready to go on my day off so I know if I come across any promblems I have the parts to put on. I tried 4 years to buy this truck I want it done right and soon so I can have it painted