okay so I have A 93 s10 blazer 4.3 vortec FI a couple weeks ago I pulled in my drive way and it died and would not start back I had been having trouble from the MAP sensor but replaced that and didn't help so I replaced the CPI unit and the fuel filter and rotor button but it was getting gas and firethe whole time but after replaceing all that it fired right up but then as I pull out to drive it a little after pressing the throttle a little it starts missing out and running very very roughly will not open up and then after all this it wont idle not it missing at a idle when I bought the blazer the guy I bought it from said thst the only trouble he had ever had was from the map sensor he said a cat had got under the hood and scratched the wires to it into but he had put them back together and taped them good and I have put several sensors from the junk yard and new plugs on but same deal running rough I jus don't know what it could any one have any ideas? thank you

 

Is the check engine light on? With a 93, it's OBD I and all you need is a paper clip to read the codes. That should get you on the right track.

Also, you did the injector, and fuel filter. Did you check the pressure/leakdown at all? Maybe the fuel pump is the problem.

 

Okay and no that's what really puzzels me there is no check engine light on? and how could I read the code with the clip would love to know how so I can give it a try and see what it says..... i forgot to mention in last post after putting the CPI and fuel filter and button on we pulled it out of the garage to start it and hit the key one time and it fired right up after it had died and would just crank and crank before i replaced all that and after firing up it died in about 30 sec then back to just cranking then my uncle unplugged MAP and it started up agin and is now running like it should im thinking it is something to do with that sensor mabe he wired it back wrong what is the proper way it should be or any other ideas greatly appericated thank you all very much

 

kay so i figured out how to read the code with the paper clip and sure enough its saying 33 wich is code for the MAP sensor so idk what to do from here really i have replaced it a cpl time with ones from the junk yard but i know they aren't all bad but i really belive its something to do with the wiring where it was cut and put back together if any one know how they should be please let me know they is a gray green and purple wire going to it thanks for any help

 

Those things work on resistance. If the wires are just twisted together and taped, thats probably your problem. See if you can find that section of wiring harness at the junk yard that has not been cut up. Or try soldering the wires back together nicely.

 

You can bench test a MAP sensor with just a voltmeter, and your lungs, too.

Part 1 -MAP Sensor Test (P0106, P0107, P0108) (GM 4.3L, 5.0L, 5.7L)

I did this just this past weekend, when my new, faulty fpr was giving me a MAP code. (I didn't know the brand new fpr was bad at the time!)