RPM versus fuel mileage

[dangerous06]

Something just doesn't make sense? I get better mileage above 2000 rpm
then if I'm at say 1500 to 1800. Just doesn't make sense. When towing mileage is horrible 6-10 mpg If I'm in OD it drops to 4 mpg! But in D 10+ above 2200 RPM.
When empty 70 at 2000 rpm is optimal 20 MPG any lower in RPM,s and it drops to 17.
I'm thinking turbo efficiency or maybe my tune?
Lost contact with my EFI guy can I get tunes from someone else?

 

[ComnRailPwr]

Could be both turbo and tune. Yes you can get tunes from another tuner. If you have an autocal its a paperweight unless your tuner unlocks it.

 

[Howling]

If you have a V2 you can run any tuner you want . I think anything less than 2000 rpm you are just lugging the motor . 4mpg is crazy low.