2004.5+ LLY Duramax Fuel Economy Poll

[gary_lucas]

Had the truck for almost a year now, put about 12k on it.

Overall thinking it's a great truck, but the fuel economy is less than I hoped for.

My last set of numbers put me in the 14.2mpg range with mostly city driving unloaded.

When I got the truck last year it had:
* Modified exhaust (Not sure what it is, going to find out tomorrow).
* Edge Juice with Attitude.
* p265/75's

I've removed the attitude module this evening for the first time. I had a bakflip installed this past week and I'm going to get a Kennedy tuned ECM for our trip down to Las Vegas next month. We'll be hauling a 3200lb trailer so I'll get a good idea of the mileage at that point.

My understanding of how to drive with fuel efficiency in mind basically starts and ends at takeing it easy, don't floor it to get up to speed, Keep it at the low end of the speed spectrum (IE on the highway keep it towards 55 rather than 70 if at all possible...)

When the current 265's start getting old I'll probably replace them with the stock 245's and hope to see some better fuel economy.

[gary_lucas]

Followup, just drove from Vancouver BC to Las Vegas Nevada and back up the I-5 in California.

Combined average of about 17.5MPG the whole way. I was towing a 3000lb trailer with a really low profile (low wind resistance).

I was getting close to 19MPG on the I-5 on the way back, going through the mountains brought it down to 17.5 approximately.

[AKMark]

First long road trip with my 05 this last weekend.

734 miles driven (per gps). I have an 80 gallon external tank in the bed that keeps the main topped off. It took 35.7 gallons to top off the external after we got home and I confirmed the main was full.

20.7 mpg, I drove 67mph (per gps) except for about 200 miles on the way back when I stepped it up to 72mph to keep up with a convoy of friends.

Considering my motor has over 16K hours on it, I'm happy.