94 chevy 2500 p/up sometimes it it wont run i have replaced map sensor ,fuel pump ,module, ignition switch

Question

it has a 5.7 350 ive checked wires they seem fine

Answer 1

it could be the ecm going bad on it,but ususlly they will go out all the sudden and the truck wont start back again,but in some cases i have seen them cause the same thing yours is doing,if it comes down to it id replace it if i suspected it of being bad,good luck.

Answer 2

fuel filter fuel treatment maybe

Answer 3

Try the fuel filter.  If that is not it than it may be vapor locking.  That's when your fuel lines are too close to something that gets hot, and turns to pure vapor in the lines in that section and feeding to the intake, temporarily shutting you down.  They do that sometimes after old age.  You can reroute your lines if this is the case.

Answer 4

is it throwing codes?

Answer 5

try checking the fuel pump relay that might be your problem if you replace all those parts try checking the fuel pump relay.