we have a 1991 chevy s10 blazer 4x4 with a 4.3lt engine. a while ago it started acting like it was skipping we pushed it off to being a bad plug. the other day we had to run into town and the truck was acting like it was skipping but 10 times worse when you would give it gas it would make a weird tut tut sound. we thought the injectors where dirty from what we saw on the net so pulled them out replaced the gaskets and reinstalled and now its still doing it. the fuel pump is new we just had it replaced this summer so we know its not that but we are at a loss on what it could be.

also now when the truck is running when you take the air intake off you can see fuel running from the top of the injectors like a small waterfall of fuel

 

You cannot be positive its not the fuel pump unless you pressure check the fuel pressure.

 

Sounds like the fuel regulator, or one of the fuel lines are leaking. You will have to pull the upper intake off to see where the leak is. You can do a " key on " pressure up of the fuel system with the upper intake off, so you can see where it is leaking. Good luck.

 

when you pull the intake off and look at it while its running right where the injectors connect to the connectors it looks like its coming from the top cause its just fuel coming from the top.

also from what ive read online would the map sensor cause this problem?