You'll be lucky to get double digit mpg numbers out of a 5.9L. They are really thirsty!!

Hemi = over 100 more hp and twice the gas mileage

 

Just an update. Did a 30 mile drive (life/work has been hectic) and I got 15.6mpg. THe overhead was reading 18mpg at one point so who knows.
I took it to dealer, they checked computer and no codes were showing.
THe service writer there was some tom boy chick who had a 1500megacab outside and she told me that 8-10 is about average for a ram around town. THe good news is is that she knows the truck and the previous owner and explained how lucky I am to get a used vehicle off him because he was an older man who only bought the best and wants teh best for his vehicles. Said she was planning to have her neighbor buy it, but I put deposit on truck before she found on. She said the tonneau I have, though a very good one, is also very heavy and adds to teh drag in stop and go driving. She also said that as I get more mileage, I might get better gas mileage because these dodge engines take longer to break in/loosen up than chevy/ford.
Im going to keep monitoring it and wait til I make a good trip and then see what type of mileage I'm getting.
THanks for all the comments. Really appreciate all your efforts.
Ill keep monitoring it.