Well, how hard have you tried?
My truck's powertrain has the same story - most people with an LQ4 report getting 11-12 mpg no matter what they do - but my own truck easily gets 14-15 in daily driving. It comes down to the details, and you gotta check them all and add them all up to improve your mpg consistently.
- Tires - you running chunky all terrains? Don't. Michelin LTX tires have loads of traction for mud or snow, but get demonstrably better mpg on the road - LRR = low rolling resistance
- Aerodynamics - do you have a ladder rack, front bug deflector on the hood, or any other silly stuff catching air like a parachute? Do you have a basic tonneau cover that you keep closed when not hauling bulky stuff in the bed? If not, do it! Tonneau covers help a lot; my nice roll up Access-vanish was only $270, keeps the bed dry, looks slick, perfectly reliable for 6 years now.
- Front air dam - many HD pickups omit this crucial aerodynamic feature, or guys rip them off themselves for whatever reason. Don't. Sending airflow around the truck instead of under it helps a ton with mpgs. I made one for my truck out of lawn edging, it helped noticeably.
- Engine maintenance - keep your oil changed on time with fresh synthetic, clean air filter, fresh spark plugs/coils, etc
- Vehicle alignment - this one is kinda sneaky. But get an alignment recently? If not, do it. Request zero toe-in, for optimal mpg.
- Driving style - COAST, COAST, COAST. No, don't be blocking traffic. But generally: accelerate briskly, then pretend there's an egg under the pedal once you're up to speed. Look way down the road ahead of you to anticipate and avoid unnecessary slow downs, and try to get into DFCO (deceleration fuel cut-off) when coasting down to a red light. I try to use my brakes as little as possible.
Lotta guys don't think aerodynamics matter on a bulky HD pickup, but they really still do. Go with the small side mirrors and add on towing mirror extensions only when needed. Pull the big long radio antenna if you don't need long-distance reception. Cover the bed with a tonneau. Don't hang a big tow hitch/ball down into the air flow behind you if not towing every day. I could go on and on - the details add up and you can probably save 20% on your fuel bill if you want to.
Also, that other dude might just trust his dashboard mpg display and never actually check it at the pump, LOL.
And finally had the winning comment at the end...
First, I'm actually satisfied with 12.5 mpg. It beats my previous truck by double in all conditions. My old Powerwagon got 6 mpg empty and rolling slow.
I run all terrains. I don't give a toss about improving mpg by sacrificing traction. We get snow here. Bunches of it. It stays all winter long. Many roads and parking lots don't get plowed at all here, or if they do, it's not very often. Spring thaw and there's mud everywhere. Can't drive down the road in front of our house without 4x4 and good tires (those evil "all terrains").
Aerodynamics... you know it's a truck, right? It's about as aerodynamic as a barn. Only thing that helps that is to drive slower for less wind to push against. I get significant savings by running at 60 mph vs 70 mph. You should try it. I try to moderate speed when possible. No sissy-fied "bed cover" here. It's a truck. I use it for "truck stuff". Summer time there's a 5th wheel hitch in it, winter time there's 1200-1400 pounds of sandbags in the bed (back to "we get winter here"). There's a ball hitch in my receiver hitch all the time. It's usually the 2 5/16 ball, as that's the one I need most often. But, it's a truck. I use it for "truck stuff".
My engine oil gets changed every 5K miles. Whether it needs it or not.
Tire wear is perfect. Alignment is fine.
Already drive it like the "egg on pedally thing".
I'm not taking my tow mirrors off. But I use my truck for "truck stuff". Them mirrors are staying. I do push them in to the narrowest when I'm not pulling an enclosed trailer, or a wide load on the flatbed trailer.
I once got 17 mpg coming back from MT one summer. I was driving in a 70 mph tail wind. That doesn't happen to me much, so I don't "count" that one.
Just funnin' ya a bit there.
