Mine says 87 is recommended.... and I ONLY use Shell and Superchips 87 Tune

Anyway, my master Dodge mechanic said that the milage would be terrible the first 2-3 tanks then gradually get better until 20K. After that expect another mpg as you reach 50K and that is that. My first tank or twoI was at 10.5 w/stock tires

Mine has about 6500 miles so far and I have found that to be right on the button so far.

I do mainly weekend HWY but 30-50 miles around towns in between and about a tank a week (250-300 mile round trips) and I'm now getting about 12-13 driving agressive. If I drive 60-65 I'll get 14-15 and loaded driving 75-80 I'll get 11-12 (I have 315's)

 

The book calls for 87-89. I know a lot of folks, including the dealership I bought it from, fill up with 87 and will never notice a differece. I decided to use only 89 because the book seemed tofavor it fortowing.

 

Thanks Timmerduder. I know a lot of folks have posted their MPGs, but not many from 1500 Mega ownersto compare to. I still have stock tires and am probably on tank #4. Hopefully I'll start to see it creeping up soon.

 

Yeah, it will creep but slow for sure. I can get 16-17 sometimes, but...

I HAVE TO STAY AT 55 MPH - no exceptions

and it better be a tank all hwy and no streets. Where I live is hills and playing in my truck after work I'm lucky to get 10.5 even now.

As far at 87 or 89, if I go anywhere besides Shell or Texaco I get 89, here in Oregon we have crappy gasoline regulations so it seems the worst gas in the nation ends up here. It is Shell and a few that actually have higher standards as well as they put the specific additives in all grades where most only put the good stuff in the mid-high grades. Hard to even find Texaco anymore....

 

lol, i love how people buy the huge engines, and immediately start asking how to get better gas mileage. you know these things aren't toyota prius' when you buy them, so if gas is an issue, especially in today's day and age, don't buy the thing.