Underhood heat?

[USMCFords]

When my truck gets warmed up after driving for a while, it feels sort of sluggish when getting up to speed in all gears. Starts and runs great, good power until about 15 minutes of driving. It doesn't get terrible, but enough that I notice. When I pop my hood, there seems to be ALOT of heat. More than any other vehicle I have. Could this be the problem? Also, I have a hole in my airbox, where the hose connects. I removed the AC condenser, as most of the fins were bent closed, and it doesnt have ac anymore. It helped some, but the issue is still there for the most part.

 

[dangerranger911]

repair the air box and change the fluid in the radiator flush if possible i had same problem but i changed my radiator it was pretty dirty also maybe the water pump or thermostat