Mk3 tropper wont start

I have 1993 chevy 4.3 pickup that about every three years does the same thing it was the fuel pump relay located on passenger side of firewall under a plastic flap. I went to parts store told them my vehicle and got relay took 5 minutes runs fine again Semper Fi!

check the throttle position senser

You have a failed IAC (Idle air control valve) its on the throttle body,

Engine stall or RPM fluctuates at idle.

This problem is commonly caused by a dirty automatic idle speed control valve and throttle valve. Buy a can of throttle valve cleaner (do not use carburetor spray cleaner!) from NAPA or Carquest (made by CRC chemicals) and spray it into the air intake while the engine is running, use up about 1/2 the can, engine will try to stall hold the speed up, shut it down and let it soak for 30 minutes, restart and blow out the remaining fluid, shut it down and disconnect the negative battery cable for 5 Min's to reset the base idle control

sounds like (TPS) throttle position sensor, also try crank position sensor aswell

well it could be many things it could be an vacume leak it could be an idel air control motor, it could be a throttle position sensor well i hope ive help a little please let me know

No codes stored? Throttle position sensor? Do you have correct fuel pressure? 49.2 +/- 5psi?

replace the idle speed control air bypass valve.

try cleaning the IAC valve ( Idel Air Control valve ) and check for vacuum leaks, also clean your throttle body and all passage ways please rate -jeff

Your cable from the battery needs to be in great shape. If this happens mostly when the weather is very hot, it is quite likely the cause.