Guys I need some help here. I am working on this 300 6 cly that I have put a head gasket and had head worked about 4 months ago. The truck runs super, but if you put a load on it like P/S or A/C it trys to stall out. I have cleaned and replaced IAC valve, checked for vaccum leaks, checked timing, checked for dist. shaft play, blocked EGR flow, checked fuel press, tryed TPS sensor, and even tryed swaping ECM, and the thing will still die when you frist crank it and even after running, it will stall under any kind of a load. I really need some help. Thanks