1990 Oldsmobile Cutlass please help

My car will idle perfect with no problems but when trying to drive forward or in reverse the engine will die very quietly. I have replaced a lot of things including fuel pump, strainer, & filter; ecm; maf sensor; throtle body, sensor; radiator; another control module thats under the hood want to say icm, and few other things that I cant remember. Please if u hve any idea of what the problem is let me know. I have way too much money wrapped up to junk it and to let it sit. Also need the vehicle to get back & forth