I'm curious about the relationship between RPMs, shifting, and MPG. When I first got my truck, I shifted around 2000 as much as possible, thinking that the lower the RPMs the better the MPG. I got around 20-21 MPG (mixed) and a have a camper shell, access cab, and 4x4.
The past several tanks I've been a bit bored, and shift now around 2800-3000. The MPG hasn't really changed at all... most recent tanks of ~75% city driving were all around 20.5. It seems like shift RPM doesn't matter as much as I thought it did.
Is there any explanation for this in terms of the 2TR FE running more efficiently at these RPMs to balance out for working harder?