Recent content by XZZZZZZX

I have a 09 tahoe z71 v8 5.3 with 38k miles using 87 octane fuel and I am seeing around 10.5mpg and 14-15mpg on the highway-long trips...Is this normal? I think the city should be higher. No mods and normal driving conditions. 4wd set to 2wd (not auto). Any suggestions on how to increase?