2015 Volvo no power

I recently bought a project 2015 Volvo with a d11 that loses power after running for 10 minutes. The def had been deleted two years before I got it and he had no issues the truck doesn’t throw any codes they tried a different computer and replaced several other parts. The fuel filter is new. after driving awhile I looked in the fuel tanks and didn’t see any obvious bubbles coming out the of the return fuel lines. Any suggestions would be appreciated.