So how fast did this come on after:
You changed your plugs and wires (Might have some distributor issues
You changed the fuel filter (maybe a bad filter or you installed it backwards, some have to go only one way)
After your last fill up (bag gas or such)
When it stops running, does everything else keep working? Radio, lights, heater etc.
When it quits in reverse, does it do it when you are shifting (some problem in the column with connections) or after a while? If after a while, after a few seconds of idling, or when you start to push on the gas?
What light comes on? Alternator? Check engine light?
Does it stutter like it is out of gas or like there is an electrical connection failing?
Is your computer still hooked up? and working? A computer controlled carb?
Does it do it more or less when it is warm?
Sorry for so many questions, but you will find throughout life that if you spend enough time and effort describing the situation thoroughly enough, the solution becomes apparent.
Let me know and I will get back to you.