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.

 

Wow...what a fiasco....unless some.one else chims
In.I would be looking into a vacuum line or some other
Loose hose type problem for the engine to be cutting
Off...im no engine knock sensor expert, but I do
know that it was changed also the EGR was eliminated
after I think 2003... your origional engine had the EGR
on the front of the intake manifold..if the new
replacement engine is a 2005 there is no EGR and the intake
Manifold will need to be swapped to get it back....

 

Check the vacuum lines connection to the correct inputs.
the brake booster uses vacuum to help you brake, maybe something wrong with the booster?
good luck.

 

That's more info than I had and a place to start. I will look into the motors' Vin and see what year it is. Thank you. Didn't know about the EGR!!

 

The egr is just to the left of the A/C compressor which
Would put it almost in the center of the motor...
Its about 3" in diam. And has a wire pluggy thing
On the end of it...kinda hard to miss.....
I re-read your first post... and miss read the 2005 part..
I was thinking the motor replacment was 2005...woops
Bit definatly check ang and all electrical plugs and any
Hoses... it could also be as simple as plug wires not on
The right plug (spark plug) so check the firing order