Engine Mechanical problem
1993 Chevy Cheyenne 6 cyl Two Wheel Drive Automatic uk miles

I have a 1993 Chevy truck with a v-6. I have replaced the fuel pump, fuel filter, rotor button, dist. cap, plugs, throttle body cleaned, throttle positioning sensor reset, and fixed what even remotely seemed to be vacuum leaks. On the road it runs fine and have zero problems. When I come to a stop or slow for lights and such it will die (just shut off instantly) and is very hard to crank most times. It even has problem starting in mornings as well.
I am at my wits end trying to figure this out and man I need my truck. Anymore suggestions to point me in the right direction?
Thanx for the help.