What are you getting for fuel mileage in your 2008 SD 6.4L ??????

 

10.6 mpg so far..... mostly city though.

 

12.8 MPG, all city. I did take a 500 mile trip when the truck had 200 miles on it. I averaged around 15-16 MPG on the interstate, but that was keeping the speed under 70 MPH. As soon as I would speed up to 80 MPH, which is my standard running speed on the interstate, the MPG dropped to around 14 MPG. I think 60 MPH may be the sweet spot. I seem to get the highest MPG at 60 MPH. Of course, I only have 1900 miles on the truck now, so hopefully that will get better.

 

This may have been answered somewhere in all the topics. But why
does the 6.4 get such bad mileage.

 

One thing to remember is these trucks are still very new. The milage should improve after the "break in" period is complete. hope that helps. Robbie

 

The reason that the 6.4L engine gets lower gas mileage has a lot to do with the higher emissions standards that the new trucks have. I am still averaging about 13 MPG around town and have about 3500 miles on my '08 F250.

 

I've read on other boards that mileage should get better at or around 8-10000miles with the powerstrokes.
On the other hand, my mileage has never changed since new and it has 30kmiles now.

Freeky, your 35" toyos are likely robbing you of 2-3mpg, mine made a considerable difference compared to the factory 20's. These tires are heavy.

 

I just bought my 80 F-250 crew cab 4x4 truck last week, the first tank of gas I got just over 10 mpg, the second tank of gas I got about 10.9 mpg, the third tank of gas I got today I got about 12.4 mpg. I have about 650 miles on it and it has all be in town stop and go traffic.


BTW this was all hand figured, it isnt off of the dash mpg.

Leon

 

08 F450 4:88 gears
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Towing 31,000lb to Colorado and back:

6.4mpg @ 80mph
7.6mpg @ 65-70mph
8.3mpg @ 50mph

I contribute the low mpg to the elevated RPM level the truck runs at. With 4:88 gears, the truck needs another overdrive gear in the transmission. 80mph is at 3000rpm... sucking fuel the entire time. 65mph is around 2500rpm, still sucking fuel the entire time.

It has power to run on the highway (any speed, does not slow down on the hills)... still slows down bad up mountain passes though. Does not move the temp gauges like the 05psd would (truck runs exceptionally cool at any load).