ignition/ sensor help needed

This is the problem...car starts runs fine untill engine gets warm ,(not hot,.. indicator shows about mid way and fan does not come ,i can hold the rad hose.). When it dies the front coil works, spark at 1 and 4,the back side has no spark. the coil has 3 wires.. center is pwr... fwd wire is for fwd coil and aft wire is for the aft coil. when it died out i swaped the fore and aft wires ...then the aft coil has spark and the fwd does not. Checked continuity from pins at coil to pcm ...checks good,Ok so I belive pcm is not giving the signal (ground) needed to energize and collapes coil , so I changed the pcm ...still the same results. has any one had this problem or could some one point me in a logical direction. THNX in advance PS... remember, test dont guess