Fuel Guage Off

[Logan22]

Hi I'm new to the forums and just need a little advice.
I just recently got a new engine put in my volvo and after driving it for a week or so now my fuel guage and miles to empty is wrong. I was getting on the highway and it showed 160miles to empty or roughly a 1/4 of a tank and the car ran out of gas. I have filled it up all the way and the needle goes to full but the needle isnt lowering in accordance with the miles im driving?

Thanks For Any Help,
Logan