That's the best and most accurate way to check fuel mileage. Fill up, drive, fill up again. Divide the miles driven by the number of gallons you add, and there's your mpg. The biggest variable there is pumping technique; in other words when you stop filling. First click-off? Second click-off? As long as your technique for filling up is consistent from tank to tank, you'll get an accurate mpg figure. Even more accurate if you use the same pump from the same station to avoid any differences between when a particular fuel nozzle clicks off.

The trip computers in vehicles that display mpg are a decent guide, but in many vehicles they tend to be off...in every vehicle that I've had, the trip computer has displayed a little higher mpg than what I'm actually getting based on hand calculation.

 

I did use different pumps but I did set them both on the slowest setting.I to have noticed both my car and truck a little optimistic on the fuel mileage and was suprised it was dead on this time.

 

There is a sticky in this section with pages of data.

 

09 crew cab 2 wheel drive , hemi 3.21 .. 20's lone star pkg.
70,000 on this truck. Drove to south texas and back 856 miles r-trip
From Dallas going south running 78 with a/c 19.9 to 20.2
coming back home cooler wheather about the same 78 mph 21.6 really good .

 

I've been very happy - 2010 Crew with 20" stock wheels and tires 5.7 MDS - I average about 18 on highway.

Having the EVIC - I tend to contour the driving to make the most of the milage. Its tempting to let the duals roar a little, but if you watch the EVIC and back off a bit - the Hemi seems to do pretty well. Its much better than my old Trailblazer with the I6 - it averaged 15.5 making the same trip.

 

I get 15.5 overall and 19.2 on the road. I drive moderately.

 

I have been trying some different driving styles myself and was kind of shocked. If I drive normal IE no hard take offs, and drive at speed limit or a little below my mileage drops. Now if I drive her hard take offs, and little over speed limit the mileage will rise. (09 TRX4 5.7) guy i work has tried this style as well with his Ram and same results. Right now in the city its 16.8 not to bad. And before someone says anything no I'm not flying through town and other things like that.

 

Gutty, can I get a copy of that spreadsheet? Doesn't have to have all the numbers just the spreadsheet with all the formulas. I like how that worked out for ya.

 

Sure, PM me your email address I am I will send it to you.

Anyone else that wants it can have it to, but keep in mind it is written for KMs and Litres, so if you enter miles and gallons it won't work.

 

USAF1, what kind of highway speeds you talking? I have the same truck. Really thinking of a tire change from the 275/70 r 17 GOOD YEAR AT/S tires to 265/70s, loose some rotating weight...would be alot better in town I think, and might more then balance out at speed by MDS staying engaged more. I know even if I managed to trade or sell the TRX4 tires, no matter how much better it does, I would still be $$ behind. I guess the TRX4 tires can last a real long time, and trailer tow good but they are more tire then I need, and I'm just wondering what if?