hi, ok let me start with what my blazer is:
91 4door 4x4 4.3L (not the vortec):
so i got this blazer in december and was told the distributor needed to be changed soon. so i drive 1400k with little to no issues, then it starts to give me acceleration problems, i hit the gas, and it bogs down. start the fun! some days it will idle with no issue, then i put it into gear and it stalls. if i start it and can get it into gear b4 it hits low idle <i>sometimes</i> its good to go till i shut it off. half the time ill get the timing right (no gun....so who really knows) it sounds good, runs good, then in gear its done. other times ill play for 2hours and never get it to run good, limp it home, shut it off, in the morning ill go out and she runs like a top! so i figure that the distributor is done for, and a friend of mine says that its a sensor. so after a month of fighting with it i get a parts blazer. i changed the distributor (third one now) new cap and rotor, newer wires, new plugs, oil and filter changed, fuel filter changed, swapped out the orginal throttle body with the parts truck's, changed and/or replaced every vacuum hose i can see, and if possable whatever they were pluged into, other than the one to the brake booster. not totally sure what sensors ive swapped out but there is only two i have not changed. one is on the manifold, the other is on the top of the block, front middle, just in front of the throttle body unit. im getting REAL frustrated with it and im about to just swap motors with the one from the parts truck!(way above my skill set) im willing to say that i know im NOT a mechanic, i do know the basics, but i stress i am no mechanic. another friend of mine saw it yesterday and thinks its a vacuum leak, but where?
oh and btw, EVERYTHING ive done kinda helps for about 10 minutes then its back to the way it was. nothing has worked....so far
i love my blazer and dont want to let it go, what do i do now? im so lost
any kinda info will help alot, im working on it almost every day and would like to enjoy the 4x4 (first ive ever owned) not just work on it!

 

Are you getting an engine light? Because distributor and electrical problems usually light up the diagnostic light. Fuel problems however, dont light it up... So it kinda narrows the problem down some. If you are getting an engine code, use the "paperclip method" to determine the codes for us and post back. Other than that you want to test your fuel pressure for constant pressure by hooking up a test gauge to the test posrt and letting us know what the readings are.

 

so, i must say i LOVE the "paperclip method"! this is what i got from here:
13 - oxygen sensor
15 - coolant sensor, low psi (i do have a small rad leak)
24 - VSS - says to ignore
33 - MAP sensor, high V
43 - ESC not receiving knock signal
44 - Lean Exhaust - Low oxygen sensor voltage
45 - Rich Exhaust - High oxygen sensor voltage

i asume 44 and 45 are because the oxygen sensor is dead or wires are broken where i cant see, i did a check and today.(its raining, and truck is running better) ill check the MAP sensor, again, but im thinking that maybe some errors are old, from before i started to change things out, is there a way to reset it, or is what comes up whats wrong at that time?

 

also want to say, i have learned alot from this forum, and now that i have 2 blazers, thinking of making one a total mudder!

 

yea since you got a lot of codes i would disconnect the battery for about 30min to reset the computer then drive it around the block a couple times and then see what codes come up.