Its fixed! That did it. I am going to have to go back and look at the CTS and MAT blend table.
I think I told you guys wrong here. Because of code 25 being set, the PCM was using -40 C as the intake air temp all the time. So this is the reason I was going extremely rich with anything other than 1 in this table. So 1 gives all control to the ECT and 0 gives all control to MAT. This is why anything lower than 1 in my tune at all was way rich, PCM using -40 C as temp to calculate fuel.
Just looking around and found a thread on Fullsize chevy talking about adding MAT.
http://www.fullsizechevy.com/forum/g...-sensor-7.html
Basically anybody that has added MAT to a TBI bin, and did not fix the code 25 issue, is not getting correct fueling.