456M GT lack of power

Got a 1998 456M GT that is lacking power, especially above 4000 RPM. It also seems very sluggish when free revving. No check engine light, no slow down light, and no fault codes. Replaced fuel filters and had fuel injectors professionally cleaned and flow tested. Any thoughts would be greatly appreciated!!

 

I checked the throttles and cable adjustments, found ok.

 

The plot thickens. I was just driving the car trying to figure out the issue when I noticed a bigger loss loss of power and the SLOW DOWN light started flashing.
The throttle response is very numb and doesn't want to rev. I check exhaust back pressure in both banks and found them both to be ok. Can a faulty catalytic converter thermocouple probe or control unit cause lack of power?

 

Looks like a fuel pump issue. The right bank fuel pressure falls off when under load. Most likely the rubber pump support is deteriorating.

 

My guess is the low fuel pressure under load is causing a very lean condition, in return causing the catalytic converter to get hot triggering the slow down light. Or, there is a separate issue with that system.