You have too little truck for your trailer... that said the tuner should help but the cost of them will buy a LOT of fuel. Before you buy one make sure you talk to the manufacture to find out what it will and wont do for you.. When you talk to them make sure you have a list of problems you are having so you dont forget anything.
2004 Chev Silverado Duramax optioned past the max. 2009 Jayco Eagle 308 RLS 765 watts of solar, 6-6 volt batteries (696 amp hour), 2000 watt (4000 surge) whole house inverter.
140 days boondocking in 2016
211/2015, 196/14, 247/13, 193/12