I think I put this in the wrong place the first time...sorry! I am new to forums!

Before I get started, I searched the threads and found one from 2005 that had the same problem, but no solid resolutions. Here goes: 1998 Blazer 4x4 drops oil pickup stick and blows motor. No problems before this incident. When driving it home from the shop, it died when I braked. Still happened randomly after I fueled.It never died unless I was breaking. Within a couple of days, the fuel pump went out and the shop got it again.

LONG story short, after they replaced the fuel pump I was forced to take it to a new mechanic.

There are three issues I need to resolve but I need info for two of them:

1) they cut the wiring harness to swap motors then wired into it. We will be replacing it.
2) they put in the wrong used motor. The blazer runs but....The knock sensor 'plug' on the motor is incompatible with the knock sensor 'plug' on the computer. Is there some type of line or item to make them compatible? The only thing we know about the engine is that it's from an S-10 truck and doesn't even have a place for the knock sensor to be mounted 9found it taped to the blck with a ton of electrical tape!!)
3) Now the blazer dies when I brake, but not every time. I don't know if it has to do with fuel levels. What i do know is that I asked for a new fuel pump. What the mechanic found was that the original fuel tank was gone, the one in it had been drilled and the 'fuel pick up nipple' had been welded into the hole with a line running from it to the fuel pump. The return line wasn't even hooked up.
I am looking for why the motor dies when breaking. This is my primary problem to be resolved. Will fixing problem 1 or 2 fix the dying issue?
The money from the lawsuit isn't enough to drop in a crate motor, new harness and new fuel system so I need to fix one issue at a time, but I need to be able to drive it now.

1998 Chevy blazer 4x4 with mystery S-10 motor

 

All i can think of is a vacuum leak somewhere when applying brakes.