Well I couldn't find the old thread since you can't search for 3 letter words such as MPG, which is kind of stupid on a car forum, so I'm starting a new one.

Anyway, I drove 534 miles from Columbia, SC to Pittsburgh, PA yesterday to visit family for the holidays. I was surprised to see my overhead saying that I was averaging 17mpg even with all the mountains. I figured it was just being inaccurate, so I did the math the next time I stopped for gas, and came up with 17.2mpg for that particular leg of the trip, which included the mountains. I was pleasantly surprised that I managed that with the 5.2, especially since I was going between 65 and 70mph most of the time.

 

I see that radar detector Thats good IMO but I do have the 5.9 with full time 4X4 so my opinion is skewed on gas mileage (last tank was 9.5 MPG around town, Christmas traffic). That being said the best mileage i ever got was last spring on my way back from Binghamton to the Island, I averaged 14.9 MPG which is by far the best my truck has ever seen.

 

according to my truck im averaging around 12.5 mpg when im working ( driver for pizza hut atm) and as much as i love my truck i hate putting this mileage on it so ive decided on getting a car (honda) to do work in and keep my D for non work stuff

 

I usually get around 13mpg around town and 16 on the highway. 17 was the best I've ever managed.

 

17 is pretty standard for me mixed driving except in the dead of winter in the summer 19 is not uncommon

 

I get around 280 miles per tank. Hit the allusive 300 from Denver to Grand Junction, CO. That's 8 up and 99 down the mountain. That's rolling 35" bfg at and fully loaded.

 

If I wasn't being captain ocd and would've let my gas gauge get below half I could've gotten 374 miles if I let it get to the E and 400 if I would've pushed it down to only a gallon and a half left in the tank.

 

does 98 have a 24 gallon or a 25 gallon tank in it? because i doubt that these pumps will suck the tanks that dry, (400 miles at 17mpg is 23.5 gallons)

i usually get btwn 300 and 350 miles out of a tank filling up when i hit the 1/4 tank left mark


the other thing i have to ask is when you fill it up do you let the pump kick off and thats it, or do you top it off to fill the filler neck? because if you do the second you will never get a great read on MPG because you wont always fill it to the same point,

 

I've got a 25 gallon tank. One time it was down really low it took well over 23 gallons. I usually do fill up the filler neck too, but the variation in the amount there is fairly insignificant compared to the rest of the tank.

 

maybe, maybe not, it is very possible to get a nice air bubble in the tank, this becomes more likely if you fill up the filler neck (along w/ the very good chance of ruining your charcoal canister by filling up the neck, but thats a whole other story).

im also curious about enviromental conditions, ambient temp (higher is better for mpg), wind (im expecting you had a tailwind most of the way) amount of traffic, smooth driving w/o slow downs is obviously better, all things that need to be taken into account when thinking about gas mileage

for example, where i live now is mostly flat, so in normal driving i get around 17 around town. lately i have been getting 14.5-15, normally this kind of drop would be a concern, however i can account for a number of negative factors,
1) cold weather (denser air contains more oxygen, requires more gas), also longer open loop run time and lower air pressure
2) lots of idling in my commute, i have to idle through a guarded access gate every morning and evening, this totals btwn 5 and 20 minutes of idling a day.
3) winter gas mix is less efficient than summer gas because of the additive package used to help prevent gas tank/line freeze up,

also i have heard of people getting a gallon of gas into the filler neck, which on a 25 gallon tank is just under 5%, not huge, but far from insignificant.

i am not doubting you, just bringing up pieces of the puzzle that many people overlook when talking about gas mileage (im sure ill come up with more as time passes)