4L60E Going Crazy. I need help!!!

[ghosterbuck]

Bought a truck with a rebuilt motor that I believe was shady built... Not totally relevant, but the trans is acting funny. It won't go over 2k rpm in gear, unless I pull it down into the gear (1st, 2nd, 3rd, etc) It will however tach out out of gear. It also likes to go dead in reverse. Is this a vacuum issue, wiring issue, or is it the TPS??? I need help asap. It's my current secondary ride, but I'm going into a new line of work and need this fixed. I would be hugely greatful for anything you guys know or even could think of. It is also throwing a ton of codes (MAP, TPS, ABS on all wheels... I changed the ground side terminal but didn't look into the ends of the neg except to see they're hooked up)

This is all on a 1996 K1500 Z71 with a 5.7L, 4L60E, and a 3 inch B.L.

Thanks!!!