gas mileage 2021 big horn with 5.7 E Torque

[massram21]

having issue with terrible gas mileage, first 2 years avg 13.8 in winter and 16.1 in summer but this year since October my mileage with same combo of daily driving conditions my milage has dropped to 11.2 avg. is this possibly gas for northeast causing it or some other issue . only 19000 miles on truck . tried new air filter ,not having truck warm up for extended times. if a lot of people have similer issue would most likely be gas . use 89 octane

 

[Darksteel165]

Million threads on gas. You don't say what gears you have or what kind of truck it is. 16 is the norm.