Killer Gas Mileage!!!!!!!

[TIE-YOTA]

Not sure whose hot and whose cold weather wise. However, being cold (36 - 47 degrees all day) in the Houston area, I have noticed that I am getting good gas mileage: 17 to 18 MPG on 285/r16's tires. I normally get around 15 MPG if I am lucky. Am I in left field on this or is this a reasonable assumption? Cannot explain why I am getting better gas mileage all of a sudden. Anybody want to chime in. Truck has 36,188 miles on it, 2004 Tundra DC 4wd.

[tundo]

Wish I was somewhat close to that figure! 13 with my 285/75 16's. Maybe you got a batch of jet fuel for gas

Ryan

[splice57]

17.4 yesterday - 2000 AC SR5 4x4 with 89k miles. About 50/50 highway/city

[TUNDRA&LIGHTNING]

Are you putting it in neutral when you go down hills?

[TIE-YOTA]

Originally Posted by TUNDRA&LIGHTNING

Are you putting it in neutral when you go down hills?

Hills? What hills? I am in Houston man. The flattest area in Texas. If not, it's damn close. I am going to see what the deal is once I kill this tank of gas. Strange. Next oil change I am switching over to Synthetic Motor Oil. Truck is running great. I am not hotdoggin' it anymore which I know has a little to do with it. Those Dodges bring out the lead foot in ya.

[v8Toilet]

Your tires are throwing your speedometer off and thus your gas mileage calculation maybe?

[student's tundra]

Originally Posted by v8Toilet

Your tires are throwing your speedometer off and thus your gas mileage calculation maybe?

Yes this is true but if he has larger tires than stock he would be counting too slow and thus should be getting better mileage than indicated.
So Question Tie-Yota : Have you adjusted your speedo/odo? Did you adjust it too much so that you are now counting too fast?
Or maybe he's just getting better mileage due to the breath of cool fresh air .

[T'sTOY]

Splice57,

Have you had your O2 sensors replaced?

I've got about 80K on my 4x4 with 285s and my mileage has dropped over the last year. I'm beginning to think it might be the sensors. No check engine light or other performance issues, just the drop in gas mileage. I hate to install new ones without a reason (check engine light), but with the price of gas these days that may be just enough to justify the expense.

Thanks in advance,

T'sTOY

[trfytoy]

Cold weather will make gasoline more dense... i.e. giving you more fuel. Although not much....

[ALL MOTA]

I would notice my car (Civic) would run better in colder weather too. It would feel peppy. Colder air combust better. Think about cold air intakes, intercoolers, and stuff like that.

[Diego]

Cold air is denser and does give more power BUT cold weather also makes everything stiffer causing more drag in the drivetrain. I also had the same phenomenon at Christmas time. I did a 200 mile highway trip, got 18 mpg on the way there, got 21.5 on the way back, can't explain it. I have never had that good of mileage before or since that time. My last highway trip a few weeks ago I got 17.6 mpg both ways. In really cold weather I am getting about 9 - 10 mpg in the city and 16 -17 highway. Imperial gallons not U.S. It might be a one time deal like I had or maybe your in luck and your truck is now getting great mileage for some unknown reason.

[Hugemoose]

I've been getting kinda worse mileage in the cold weather around here. But I think that's because I let it warm up awhile, plus i only drive short trips here around the campus. Good part is that I normally don't get enough time to warm it up enough to really get into it

[TIE-YOTA]

Yeah, I thought the speed-o-meter situation. However, in all cases, trend shows that you will get worse gas mileage with larger tires. Being that the tires are only an 1.5" larger in diameter than stock, I would think it probably makes a difference of 2 to 3 mph. At least on my Taco with 33", that was the case. The interesting thing was when the Taco reached 80 mph (not recommended), it was no longer a linear difference which means the spread increased to about 5 to 7 mph. A policemen pulled me over one day, a long time ago, and said I was going over 95 mph. The speed-o-meter only read 85 mph.

Another point was after Hurricane Rita hit, gas was short all over town which meant you had to get what you could find. With that said, I did get some bad gas that tripped my check engine light. The dealership said the truck had traces of bad gas in it and the O2 sensors were changed. Good feedback and comments guys, thanks.

[splice57]

Originally Posted by T'sTOY

Splice57,

Have you had your O2 sensors replaced?

T'sTOY

I replaced both front O2 sensors at 45k - my light came on for the front passenger sensor, but I replaced both. Haven't had a problem since. I did lose gas mileage when I simultaneously lifted the front end (2in spacers) and put Bridgestone Revos on it (stock size). I attribute this to increased rolling resistance and reduced aerodynamics. I religiously change my sparkplugs with the OEM 30k ones, use synthetics in both the engine and differentials, and keep the air filter fresh. I'm also about to change the fuel filter just because. When I had my old, bald OEM Dunlop tires on it and a good tail wind on a 600 mile trip, I actually got just over 20 mpg on the interstate - almost 600 miles to the tank!! Have never been able to duplicate.

I drive fairly conservatively and I think that gives my good mileage.

[yspert]

Had you been running the air conditioning before it turned cooler?