2003 Ford Expedition

Engine loses some power when it has been running - when it has been running for 30 plus min. - Doesn't matter if short hops or long runs. Power loss not dramatic - but I am primary driver and notice. Particularly on a hot day - vehicle reaches power loss state earlier than a cold day.
Power loss is accompanied by hesitation at steady acceleration. If you put your foot in it, as my husband does, the engine responds by downshifting and gets on down the road. But, that is not normal driving.
We've had the injectors cleaned, replaced the PCV hose in the past 3000 mi. A side note - we killed the catalyst by adding cleaner and cleaning the throttle body. They (4) were 60% blocked. The catalysts have since been replaced. We haven't messed with the throttle body for about 10,000 mi.
Never ran hot, no teenagers drive, but pulls a boat 5-7 times a year 1 hour each way to the beach.
Love this truck and want to keep it.
What are your thoughts?