The only way I can explain the 225.5% decrease in fuel economy is a good bit of that first tank was on the interstate as I bought the truck out of my area and had to drive it back into town. I also varried between 60 and 70 mph on my trip home. It was also late at night (midnight) where the air temp was cooler and it was extremely less humid than the last few days since we have had serious rains related to the tropical storm. Cooler Air and Less humidity give better gas mileage. Cruising at a constant speed also give a lot better gas mileage.

I also don't remember how hard I drove my 1st tank either because I knew it was a new truck and kept the needle under 2k rpms. This has a large affect on gas mileage (near 1.5 to 2mpg on the old truck) but I do know for this last tank I drove the truck like I normally drive a vehicle.

The other assumption of error I could make was the fuel pump clicked off too soon when I was filling up the tank thus leaving a large portion of the tank empty. When I went to fill up again to calculate my mpg and it might have filled up the tank completely, and it would have thrown my calculations out the window.

Not sure what to say to this post other than you must not have read the entire thread.

I believe my #'s to be accurate. I NEVER used just the fuel guage to judge how much gas I had used in my truck. I simply was stating my fuel guage on the dash was reading I had used up a 1/4 of a tank when I fueled up at a gas station. I used the #'s off the pump though for calculation purposes.

I incorrectly assumed I had a 20 gallon tank because my fuel guage seems to move around more than the last one. This made me incorrectly assume my truck has a smaller tank BUT, this assumption would have absolutely no affect on my calculated miles per gallon.

I've been checking mpg for the past five years and 60k miles with my old truck. I did it the same exact way on this vehicle. As far as I'm aware my #'s are correct. I watched that gas guage move down quickly in a short (25 mile) commute and I have never seen a guage move down so quick. Even when I use to take my old truck to the drag strip and would do run after run. If any error occured because a trip meter was reset (highly doubt as odometer adds up correctly) or the fuel pump at the station clicked off too soon, then it will show up when I fuel up again. If this is the case, then I will be excited because I'd love to get 17.8mpg average for my tanks of gas. I just can't handle single digit #'s... Sure, big truck, etc. etc. but they're far from single digit bad vehilcles.

It just turned up to be large shock and no where do I see sloppy calculations. I only see bad writting in my first post on my part. Misunderstanding and incorrect assumptions in the rest of this thread.

 

Thank you for the information. I hope this is the case. I talked to a friend who had an 04 and he said he didn't even bother to check the gas mileage until around 3k miles because he knew they got bad mileage in the beginning. He just told me to keep driving it and if it doesn't improve, go back to the dealership.

I think I'll just keep driving it and see what it's like after I get over 1000 miles. 13 or so mpg in the city I could handle, I did it with my last truck when I drove it hard but I use to get 21 mpg interstate. It'll be upsetting if I see I could have bought a truck I've been want but didn't because of the difference in gas mileage if it turns out there isn't one.

 

There is something about these trucks on some of ours that is just not right.

I have over 15,500 on mine now and I DO fill up at the same location and I have NEVER gotten over 14 mpg except once when I got low 14's. I am averaging 9-10 city and 12-13 highway. I have made it past breakin I would think and nothing has changed.

Don't expect it to.

 

i got 14.31 with about 80 % of city driving. I kept my rpms below 2k the entire tank of gas. It was hard but I did it. I suspect on all highway I could get 16-17.

my truck has 3.73 gears and is a 4x2. truck has 1415 miles on it.

 

I get 12.5 with city driving and keeping my truck WOT until I have to use the brakes, and all the way to FT Lauderdale from Daytona I was able to get 16.6 mpg driving all the way here around 85 mph.