4.3 half throttle stalls

[DAS2020]

This started today, idles fine, give gas say to half throttle it stalls sluggish almost dies. New cap, rotor, wires, plugs, may sensor, throttle position sensor metered ok. Seems to be catalytic convertor plugged? Could it be doing this?
Also fuel pump was changed about 50k miles ago, which I understand that doesn't mean anything.
I did have air intake tube off, running, and when it gets real sluggish I sprayed good carb cleaner in it, didn't make a difference.

[DAS2020]

Just checked fuel pressure on rail, was 55 to 60 psi, stayed in that range.
Had it running, and stalling, check Temps on exhaust before catalytic convertor was 825, backside of convertor was 600 degrees. Could it be plugged, creating backpressure,?

[AstroWill]

Does it do this only when cold, or when warmed up as well?

Is that pressure with the engine off or running?

Pulling a front o2 sensor can quickly tell you if the converter is clogged, but you usually see that more at speed than at idle.