Are you using the AC idle kick? I have a relay on my AC that goes to an input on the MS3. It will automatically add X amount of steps to the IAC when the compressor kicks on. I also have the idle advance table setup so the timing advances to keep it from killing. This hemi needs so little timing at idle, it must not be making any torque. The AC alone puts a decent load on it and without advancing the timing it would die.