how long do you have to return a new car in Utah?

Question

i got it yesterday

Answer 1

most states do not have a "cooling-off" period. That means you probably can't return it.

congratulations---you just bought a new car.

Answer 2

I'd guess 72 hours..
That's the typical time you're allowed to cancel a contract; even if you paid cash for the car, you've entered into a retail contract.
I'd get it back over there today.
Don't let them tell you you can't return it, but expect them to try to stick you with a "restocking fee".
If they do, it's gonna hurt.