I have 1993 blazer with vortec v6 4.3 w engine. It will run for a short time then it gives a sputter and dies. Normally you can just put it in nutral and it will start back up just to die
again. Sometimes though it will not restart at all. Now, when all this happens all electrical still operates normally. I've had all tests done to it, but unable to get any readings of codes. So, I figure fuel pump.So, I put new pump it ran just the same.I've been fooling with this thing since November and I'm at my wits end with it.

 

with these things it could be a # of things, for me it was the IAC valve but like I said it could be a number of things

 

my 94 S10 Blazer did kinda what your explaining. But when it started to die if you put it in nuetral and gave it gas there was a black cloud out of the tailpipe. It was also ******* really bad when trying to accelerate.....does your truck do anything like this?

 

i have a 96 blazer 2 door zr2 that did the same thing with the black smoke and the puttering. I thought it was the throttle position sensor, it work for a min but did it again. i put a new fuel filter and a new fuel pump in it. still does the same thing. i was like f*** it i took the motor and trans out and i put a 350 vortec with a 700r4 trans and with another fuel pump that pumps 5-9psi.