Hello, I have a 03 6.0 in my 95 1/2 2wd chevy truck, the engine has a Texas Speed 224R cam, their double spring's and hardened 7.4 pushrod's, with Pro Gear timing chain and Melling high pressure pump, I also have an 80 mm TB. I have a reworked original 03 harness from nelson performance that they converted to drive by cable for me, and I also had my computer tuned by them. I finally got my truck running on Thursday, and it's running good all, but I am staying in open loop, and I have 2 codes saying no signal from bank 1 sensor 1 oxygen sensor, and also no signal from bank 2 sensor 1. I have talkted to Nelson twice and they have been very friendly and helpful but I still haven't been able to fix the problem. I am using the oe 03 sensor's on the engine and they have 31k miles on them, I realize they could be bad, but I want to make sure before I go spend money on new ones. A tech at Nelson suggested that I try to ground my snesor's like the 99-02 sensor's are originally since I converted back to drive by cable, so I did that and no change. I have also ohmed out the wiring between the 02 connector's and the pcm and everything show's good and is pinned to the right positon. From what I have read the 03 and up 02 sensor's are grounded through the pcm, and the 99-02 02 sensor's have their own ground buss, but like I mentioned I have already tried grounding them like the 99-02 are. I am unsure of what to do next, but I really want to get the engine running in closed loop. Thanks for any advice!