GM-GMC: 1989 GMC S-15, spark plug wires, screw driver

Question
 My truck has been acting up for a week now, it stalled after driving it for about 30 secs, so i changed the distributor cap and rotor, it would just start and then die 5-10 secs after.  I added some fuel injector cleaner to the gas tank, and tried again, it started and stayed running for about 10 mins, I drove home and changed the fuel filter, i took it for a drive after working on it and it died again.  I then got it towed to a mechanic who proceeded to tell me that it was my fuel injector that was making it not run, so i got then mechanic to change it, still wouldn't run after that, he then began to tell me that he though that my gas tank could have been contaminated, discouraged i got my truck towed home and proceeded to take the gas tank off, i cleaned the gas tank put new gas in it and started it up, still wouldn't stay running.  I talked to the meachanic the next day and he said that next on his list would be my ECM, so i got a remanufactured one and plugged it in, still nothing has changed.  Any enlightment on this situation would be greatly appreciated,

thanks  Mike Hepting

Answer
hi mike,  

  What motor is in you S15? And what does the truck do when its stalls? Cranks OK but does not start.....I'm guessing? If so heres a simple test. Get a helper to help you work the ignition. Pull off one of the spark plug wires and use a spark tester to see if there is spark at he wire when your helper cranks over the engine. If you don't have a spark tester use a philips screw driver pointy end into the plug wire boot hold the insulated part and hold the shaft blade of the screw driver up to a gound(engine bracket or bold) about a 1/4 of an inch away, crank the motor and if spark is present it should jump gap between the blade and the engine ground. This is pretty much all I can advise without knowing if there is spark and what engine is in the truck. Let me know how you make out!