Why does my 2013-2018 F150 EcoBoost throw a P00440 only under load, but clear at idle?

I’ve scoured the F150 forums and everyone’s guessing. Here’s the scenario:

• Check engine light triggers P00440 during acceleration/decibel boost
• Code doesn’t store during idle or low-RPM operation
• Fuel tank pressure DTCs intermittently, but smoke test shows no evap leaks

I’ve swapped the purge valve and vacuum pump with known good parts. The charcoal canister vents cleanly under manual vacuum. What’s causing this thermal/cyclic failure under boost? I’m suspecting a faulty fuel tank pressure valve or cracked diaphragm in the canister, but every ‘fix’ thread says to replace the PCV valve first.

Who’s seen this on the EcoBoost’s turbo coupling? Is the pressurization solenoid triggering a ghost code during rapid throttle transients? Let’s settle this.

P.S. If you say 'just replace the gas cap' I’ll have to laugh until it’s confirmed to have 16 psi vapor tension rating.