I sold my truck because it was parked and costing me $400 per month on the payment alone. I sold it and paid off the little bit I owed. I own a honda now and I get anywhere from 25 to 28 mpg average...not highway.
The way I see it, you really need to get out of a monthly payment. If you can sell your truck and buy an S10, Ranger, or Tacoma with cash then you would really feel better about your financial situation.
However if you are gonna swap one truck for another while keeping a payment and saving $20 on fuel (at most) then I don't really see the benefit. Being debt free is what you need to be when money is tight.
Best of luck with whatever you decide.