Any suggestion at this point

 

Does anyone think it could be the computer. I had the codes read again and the same codes that I've changed out the sensors to all came up again.

 

I had a similar problem but I have the 4.2. Pretty sure it is the same tranny though, 4R70W. My speedo stopped, all kinds of lights came on, OD light flashing, cruise quit and multiple engine problems. Also the transmission was having a very difficult time shifting. I was convinced it was the transmission was bad. I bought another transmission and began the process of replacement. Once I got the transmission out and was pulling the old studs out of the manifolds I had to move the wiring harness out of the way. When I did I noticed there was a hard knot in it. I put my light on the knot and there were about 17 wires in the wiring harness. 8 of those wires were melted together and in two. 5 of the wires were just melted together. I came to the conclusion that the tape that held on the clips on the harness for the purpose of routing and securing the harness has dried out and failed. This allowed the harness to fall down on to the exhaust manifold and melt the wires. Luckily I got the majority of the wiring harness with the replacement tranny and was able to replace it wire for wire and color for color. After finding this issue, I figured the tranny was fine so I put it back in and hooked it all up. Everything is now working perfectly.

On a side note, after talking to one of my mechanic friends, he told me that until 04 or 05 there were no TCMs and that the tranny was run completely by the PCM and that there are multiple engine functions that depend on the feedback from the transmission. This being said, a lot of issues that appear engine related may actually be tranny related but are affecting the engine as well as other systems. Learn from my mistake, you can get the harness out without removing the tranny. Take a 10mm bolt out of the connector on the PCM and remove the connectors from the transmission and your O2 sensors and the harness will come out of the top. I really hope this helps.

 

That is awesome I'm going outside right now to give that a shot. This has been a big help and relief. I was thinking the worst also. Like ecm or tranny...