I recently bought a 2017 Ram eco to pull a travel trailer. Truck is 4x4, Laramie Longhorn. Lower than expected mpg, very sluggish low-end torque. Is this common for the year? 70kmiles. Built in Canada. Also, dealer said had 9000 lb towing capacity but find different weights at different sites so I’m not sure what the truth is. Travel trailer is 6000 lbs dry weight. Suggestions?