Bad mpg and power 4.7mpg

[Trey7981]

There are no check engine lights on the last one was for a particulate matter sensor which was replaced. Which sensor is the exhaust back pressure sensor. Both nox sensor have also been replace truck has 548k miles. And there is a random misfire very random. Exhaust back pressure sensor was replace a year ago september.September. just had a pm at loves and they pulled engine codes 1 active for def temp update spn 3031 fmi 9. And alot for bendix system.