Just purchased a used 2020 AT4 with 18k. It has the Goodyear duratrac tires which are insanely loud, and I know the truck has descent control but even with that off and being on a flat road letting off the gas feels very odd, feels like the truck is being held back or pushed back and it’* almost like it’* slowing down but it’* not. Anyone else with an AT4 have a similar situation and curious as to why?

You'll get used to it.

mid that how it’* supposed to be?

Depends on what you're feeling. It'* hard to judge solely based on "feels like the truck is being held back or pushed back and it’* almost like it’* slowing down but it’* not". Maybe we could give a better idea with some numbers like "while in drive on a flat road with no headwind or tailwind, when I let off the gas pedal at 60MPH it slows to 55MPH in 5 seconds" or something like that.

That having been said, noisy tires suck energy. If you have "tires which are insanely loud", remember all that noise is lost energy. It is created by tread moving through the air as well as tread blocks flexing against the ground.

What pressure are the tires inflated to?

41 psi, that’* what the truck itself recommends. It is winter in New England though so you fill it up, by the next morning it’* back down again haha. Do you happen to know if the AT4 has an engine brake because that’* what it feels like, better description than what I stated before.

No engine brake unless you are commanding it to shift down or not allowing it to shift up.

Buy a Pulsar LT from Range Technologies, delete DFM, and increase throttle sensitivity. All your power problems will be solved.

I wouldn't solve a problem that we haven't fully identified by modifying anything.