I'm runnin a 285/70/17 on my 01 4.6 4x4 and I'm seeing mid 15s to low 16s. I also check my MPG every time I fill up. Truck stays at 1500 running 60mph. 50mph=1400.
Hope that helps.

 

I baby my truck (5.4)I have stock 265 70 17 tires right now soon to change to 285's but I see 16-17mpg with mixed city and highway dont know my gears but its smooth I barely feel it shift and I can be cruising down the highway 70mpg and im just seeing 18-1900rpms

 

Im not talking bout when your at speed, Im talking bout when your getting up to speed how hard do you take off? What does your tach get to..

 

Being so obsessive and **** about squeezing every drop of fuel for all its worth is just stupid. You're driving the wrong vehicle.
I'll drive easy for a few minutes or a few days - then I'll tromp the go pedal and give it a run once or twice or 6 times.

You might as well be asking how RPM's at take off affect how many ten thousandths of an inch of rubber get worn off the left rear tire.

 

I do the exact same thing. 14 with a 5.4

 

To clarify, when accelerating from a dead stop, I don't push it, (I have a 91 Z28 for that). My truck doesn't get above 2,200 RPM. And that is driving anywhere, in town, highway...

The reason I included my cruise RPM's is because my dad has a 98 4.6 2wd regular cab 8ft. 85,000 miles. (90k less than mine) And his truck does not cruise at the same RPM's that mine does, he also has a 265/70/16 I believe. According to my Oasis report my truck is running a 3.55 LS.

 

Gotcha. mines bout the same as yours give or take a hundred....

 

The only reason I keep up with it is Im curios to know what its getting. but then again why spend $90 at the pump when I could spend $80....?

 

Full stops at signs, no rolling stop bs. 1500 - 1800rpm up to speed

 

Now if cruise is set and a slight incline occurs, torque converter unlocks it hits no more than 2,100 RPM. You won't be disappointed with the 285's