STILL NEED EXPERT HELP

2015 Honda Rancher ES 420

At a quarter throttle it bogs down and starts cutting out, and even shuts off when it’s cold. Acting like it’s not getting enough fuel. But will run good at full throttle. Before you comment read what I have replaced.

REPLACED
Whole fuel pump
Injector
Spark plug
3 main relays
Fuses
Fresh gas
New air filter
IAC Valve is clean
Valves have been adjusted
Battery is good
Vent lines are good

NO ONE ON EARTH KNOWS WHATS WRONG