Bad knock sensor, full of water. Replaced both and the wiring with GM parts. I didn't catch the part about 15 foot pounds. I proceeded to pull it back apart, used new GM sensors in cause I had over torqued the first ones. Now I still have the codes for low signal for both. I have checked the wires to the ECU , no problem found. I am almost convinced the ECM is bad although the truck runs fine. Any one have any ideas because I am fresh out.