Still having an issue with my Blazer shutting off randomly usually when coasting or pressing the breaks. Now after I just replaced the master cylinder and break booster due to a leak and having to mash breaks down to stop, the rpms will rev up and the oil pressure gauge "dances" around but usually increases in pressure when I press the squishy breaks. Any ideas? I've also been told by a friend driving it too that it has back pressure and the breaks sink at time...not sure really what he means or if it's the same thing I'm referring to.

I did just read this other reply to a post that is similar to what is happening with the random shut off and wanted to know if this could work;

****Its the CM that is mounted on the heat sink right at the top passenger side of the engine.( Aluminum heat sink...cant miss it..right at the top. the icm is attached to it)
take the whole assamble ( heat sink and CM mod) off the braket its mounted to because this is the cause of the problem. The bracket is mount to the engin and IT conducting heat back up from the engine causes all the problems.
After replacing the CM and applying the new heat paste, tye wrap the entire thing on the cables coming from the gas peddle to the top of the engine that are right in front of it , in such a manner that the air flow from the radiator will run down the length of the heat sink fins.
Simply tye wrapping will work fine and there is just enough length on the wires to the CM to allow it to reach.
This WILL finally solve this vexing problem. Simply put it is a design fault.
The CM is heat sensitive and is mounted to a heat sink. the problem is the bracket that ITS mounted to is hotter than hades and conducts the heat back into the CM via the heat sink.....crazy but do what I suggest and THAT problem is fixed...

 

You must have gained chaos mastery skills I don't see a clear picture with Your description. Your engine shuts down when You're pressing brakes? Or increases rpms...? Or increases rpms and shuts down?