So the suburban has developed a major drinking problem. I just back from a tip to all over in fl...

low down on the suburban for those that dont know. its 01. 2500 8.1L 4l80E trans 3:73 gears. 33.5 inch tires. 2" leveling kit. Volant intake & ram air scoup, JBA long tube headers, Gibson cat back..


Bristol to PortXXXXXXXwort ga ( printer is half out of ink) Tom Tom varified average speed 76.8 mph

414 miles. 36 gallons 11.5 mpg.

Prot what ever the hell Ga to Clear mont FL, Average speed. 79.6 mph.

412 miles. 37.1 Gallons... 11.1 mpg

Refill In Clearmont after running to disney and down to clear water...

363 miles, 32.2 gallons 11.2 mpg

Clear mont FL to walterbro SC, Average speed 75 mph
375 miles 32.1 gallons 11.6 mph

Walters bro SC to the crib. Average speed 79 mph
405 miles. 36.5 gallons. 12.6 mpg

So what the hell is killing my mileage.

I went to 400 miles with it with a car trailer est 3K lbs and freaking car (08 chevy impala est 3200 lbs) and got 13 mpg with average speed if 74 mph
Our underpowerd 6.0L tuck (crew, 4x4 with 4:10 gears) towed the suburban from richmond home with average speed 76 mph with 9,000 lbs behind it and it got 10.9 mpg over the 400 mile loop.


So whats up? mass air? dirty injectors? or it just likes to drink...

RPMS at 80 mph are 2300.. where as the truck with the 6.0 is 3100 rpms. The title on the turck says its 5980.. the sububran says its 6980... So there is no HUGE weight difference.

any suggestion...