OK. Now the problem maybe a partially plugged fuel filter, or a weak pump.
Ignition systems can break down under load, even though they are fine for light throttle. [it takes more electrical power to jump the dense mixture at open throttle, and a miss can occur]
A fuel filter is good maintenance. I am not a person to throw parts at a car, but this cheap part is worth it anyway.
Plugs, their wires, and coils may be faulty.
Still tough to internet diagnose without hard evidence.