[s-cars] Cold Stumble - Fuel cutoff?

[James Shackelford]

I still don't know what is causing my issue.  I just drove home from DIA
today, and it was bad for most of the drive, the new thermostat that I
installed while doing the T-belt is a little colder than the old one.
Though, after reading all the post I have some other input.

My issue does NOT occur at idle even when 10 degrees like it was today.  It
idles fine with no issues.
It doesn't do it at high boost or in the summer.
It feels worse between 1500 and 3000 RPM.
It did it today at highway speeds in fourth gear above 4000 RPM.
It is a total %100 loss of power, almost like the fuel is being cut off.
It doesn't jerk the car as extremely over 4K RPM, probably because the
engine is moving fast enough not to jerk.
I REALLY am starting to think some fueling issue.  To loose all power for
1/2 of a second doesn't indicate 1 or 2 cylinders not firing.
It seems very much like a total loss of all spark, or a total loss of all
fuel.  It has to be one of those two.

Spark?
POS are tested good.
All coils bad, highly unlikely.
New plugs and boots.

Fuel?
Need to test voltage at fuel pump.
Fuel pressure regulator?
Will run a thankful of BG44 and see what that does.

Still looking,

James Shackelford