My 1989 gets 19 mpg on a bad day. My brother just bought a brand new 2007 Chevy Duramax 4x4 crewcab and on his first 240 mile trip he got 15 mpg! Is this what he can expect?

I'm liking my 1st gen even better.

Edwin

 

It should get better as it breaks in. That's been the case with both of my uncle's. He gets around 20 on the highway.

 

My dads mileage on his 03 was really nice after 20k. He would get about 20 mpg on highway trips.

Once that truck gets broken in he should expect to get close to 20. (If he has the allison, cause they now have a double OD).

 

16.5 on my the 06 gmc 7,000 mi

17.5 on the 03 dodge 66,000 mi


All on winter blend, and both are all around driving

 

My dad has a 01 LB7 with a six speed and gets on average 20 mpg. This is calculated without taking into account his larger tires.

 

dad's 02 with a six speed stick running 70mph on the flat will get 21 22mpg. 4x4 3/4 ton all stock.

 

The new Dmaxes seem to be getting close to the old ones, maybe a shade less.
My truck, heavy foot (85mph) on a road trip, empty, flatland, gets 16-18 avg during the summer. Gets 20-21mpg driving 55-65 on the highway.
15mpg before being broken in is not too bad.
Check out dieselplace.com, theres a million guys over there comparing fuel mileage.

 

I get 32mpg towing 32,000 pounds GCWR uphill on a 105* day!


no but seriously, with diesels it depends completely on how you drive. Cruising STEADY on the highway in the summer, around 18mpg if the highway doesnt have a lot of hills and I keep it at ~70mph, 15 or so in town.

winter blend fuel stinks, maybe 14mpg highway.

10-12mpg towing, depending on load

 

Mom's gets an average of about 16 regardless of highway or city.

 

ok I'm having a brain fart...help me out guys...if i get bigger tires and do nothing to adjust the speedo for that...what happens?...do my mpg calculationss get worse or better?...i mean with bigger tires and no adjustment am i cheating myself?

 

i think you are right if you are talking taller tires your odometer will read 100 miles and you actually drove 105 miles. takes energy to go that extra length. then wider tires and taller tires will hurt your mileage so will a lift kit as you well know.

 

YMMV