1999 chevy tahoe 5.7L
ALL NEW BELOW-
THROTTLE SENSOR
FUEL PRESSURE 60-65
NEW CAP & ROTOR
PLUGS N WIRES
FUEL FILTER
KNOCK SENSOR

ONLY WHEN HOT I HAVE NO POWER. I HAVE TOI FEATHER THE GAS JUST TO MOVE. AT 65 ON THE HIGH WAY IF I GO TO PASS AS SOON AS IT SHIFTS DOWN IT BOGS DOWN AND LOOSES ALL SPEED AND AGAIN I HAVE TO FEATHER THE GAS TO GET GOING. ANYTHING MORE THAN 5% OF THE PEDAL AND IT BOGS DOWN.
AGAIN ONLY WHEN ITS RAN FOR AWHILE THIS OCCURS...WHILE COLD IT RUNS PERFECT.

AT A TOTAL LOSS NOW!!!

 

Is this original fuel pump? I know you say 60-65 psig, but that reading is cold (or I assume).

 

Something else you may want to check, especially of a vehicle of that age is the vacuum hoses going to the throttle body.

I had a similar issue on my 94, and new hoses helped a lot.

Also check the injectors for proper spray pattern. They may need cleaning.

 

I had a similar problem. My catalytic converter was clogged and was bogging down my exhaust. Maybe you should check that out.