It's been going on for awhile now, and I'm just scratching my head. The truck only has 9,500 miles on
all of its ignition components and fuel filter. Tires were more on the hyper-miler side of pressure, snow tires were just recently installed. My timing is correct, plugs look good, and the air filter is at about 2,500 miles. It has an upper grille block, WAI and is lowered. Not carrying cargo and driving patterns haven't changed. The only difference around the time of the drop was pulling out year old M1 5w-30, and replacing it with (German) Castrol 0w-30 that I had on the shop shelf, just to get rid of it. Trans bands were adjusted 9,500 miles ago, TV cable adjusted, and the transfer case was rebuilt, both filled with a fresh fill of Castrol ATF+ 4. Power steering was flushed with synthetic and the rear axle is filled with Amsoil.
EDIT: Alignment isn't showing any issues, brakes looked good at snow tire install. Cat and 0² were replace 9,500 miles ago. Exhaust isn't showing any more carbon than usual.
Only issue I could think of, and it's just this tank, is the coolant gauge is acting wonky. Sensor bench tests good, as does the wire feeding it, but the gauge shows well below cold.
Any ideas? I'm a little embarrassed only getting it's EPA estimate.