Mark_

That is true to some extent certainly. But, if you read further in the thread you will see that the posters that posted that their trucks slowed down either were mistaken or had a truck with a 4 speed. The 6 speeds do not slow down (at least ones mated to the 4.6L - I suspect the 5.4 performs exactly the same), it is a function of that transmission and its failure to downshift past third.

Tire composition would make some trucks coast a little higher or a little lower but its not going to change the fact that the truck is programmed to stay in 3rd gear at 1000 rpm as long as there is road. This works out to around 14 mph, maybe a couple mph more or less depending on tires.

shortride

iTrader: (1)

I was only suggesting that a larger and heavier wheel and wider tire could and most likely create some drag. It would not be a good comparison with a stock truck.

ji603

Sure. I drive like a little old man. For a while, it was reading 21.5 lifetime average, but this winter fuel and a few mountain grades with cruise at 70 killed that- and it's been at 20.6-20.7 for a few tanks now. With 40k miles, it takes a lot of mileage to affect the average.


I try and keep below 2000rpms. I drive 65-70 on the freeway if I can do it without backing up traffic. Easy on the gas and brake. I leave for work at 4am, and there is no traffic. My surface streets are empty too, and I can time the lights since my commute has been the same for 10 years. The truck is a 2wd with 3.55.... My true mileage (i track each tank fill with an gallon vs odometer reading) is a bit lower- like 19.1, but I have towed a little bit with it, and I get 12mpg towing.

Pretty good truck- seats more, rides better, is quieter, and gets better gas mileage than my old 2.7L toyota tacoma.

21RRF150

iTrader: (1)

I have found cruise control at about 65mph to be what works for me. I was getting around 14-15mpg driving normally. Now i get close to 17mpg with cruise.

Rok

Late reply sorry but mine actually maintains the 15mph no matter what.

DanPJR

Mine stays at 14 mph at 1k rpm and it also stays at 10 mph at 1k rpm never noticed this until I read this thread.

blue beast

tryed it tonight and mine holds the speed too

Mark_

Same here as far as driving style. Same setup with rear end but have never seen more than around 19 on the display. We do reset it often and it sounds like you have never reset it even once! The display mileage is about 1.5 mpg optimistic then, which is pretty typical for cars I have driven with the mileage readout.

You are doing really well! Most of these trucks get around 15 from what I hear. On a flat road with the cruise set at 70 I think the display was right at 21, its EPA rated highway mileage, but we never managed to get to 20, even on a mostly highway trip.

Nice truck and good engine but the mileage and the transmission have been disappointing.

PS. I wonder how much fuel has to do with your relatively good mileage. You mentioned winter blend gas. Are you able to get pure gas in AZ in the summer? Here in CA the gas is adulterated with 10 percent ethanol (with its lower energy content) all year round.

ji603

Yeah she does pretty good. Here's what I usually see.



No ethanol free gas in my neck of the woods- all 10% ethanol. we have a handful of 100% gas stations left, but they are on reservations or way out of the way.

Mark_

No ethanol free gas here at all.

I just looked up Winter Blend gas to see what was really in it. Pretty interesting. Looks like they add propane, butane, and some other lower boiling point compounds. Winter gas is actually more expensive and has higher octane but it has a little lower overall energy content because some of the added compounds have more oxygen so it takes more fuel to achieve the desired 14.7:1 burn.

Does your truck shudder and shift harshly on 4-3 downshifts on coasting down around 25-30 mph?