I got mad at myself for almost giving up and pretty much finished it

Most of it was way too easy once I calmed down. I might start pulling the extra 4x4 wires etc out of the 5.3 harness before long
Did anyone ever figure out
1)why the gas gauge reads pegged all the way past full
2)why the gear indicator only works in P R and 1
Also, what do I need to do to connect the 5.3 pcm to the OBD2 connector in the truck? I was told it's just one wire?