93 gmc stalls when idling

i have a 93 gm pu 4/4 (454eng.) i use this truck to plow my driveway in the winter but it has been stalling when in low rpm also when i put it in gear and accelerate then it won't start it is like turing the key off, after a while it will go again . i been reading forums and simaliar problems seem to be leaning towards sencors i'm not quite sure were to start.

would appreciate any help

truck is fixed . i kept reading the posts i found a guy had the same problems with his truck ignition module i replaced mine its good now!@!!!