I have been getting 15.5 to 16 mpgs up untill 3 months ago. When the weather started to get cooler it started to drop. Now on any given day I am only getting 11.6 to 11.9 mpgs. I have also done more mods to the truck like 33x12.50s and a custom bumper with winch but I cannot see any of that making my mileage get this bad. And I did the tires after it started to get bad. I have just over 19k miles on it also. Need help, can't afford this anymore. And all of this driving is around town, it never sees the highway.

 

Its normal to have a change like that after stations switch over to winter gas (not sure if GA uses winter gas). For example I was also getting around 17(city) during the warmer months. Now with winter gas I get ~13.5. I haven't make any mods. I could see your mods causing a 1-2 MPG difference.

 

that's what I thought first but my dads 09 cc 4x2 on 20s is still getting the same. We both drove to kansas for christmas and he was getting 18-18.5 and I got 13.8-14. Filled up with the same gas, but I had to more often. I think something is wrong with my truck

 

Get a car. You seriously bought a truck and then added weight and heavier tires and now are complaining about it getting poor mileage? Thats the nature of the beast here. But in all honesty the winter gas is what is hitting you the hardest right now. Like wmichell227 stated, your mods that you listed will drop you about 2mpg all by themselves.

 

All I have ever had is trucks and have never had a mileage issue like this. I can understand a drop but I'm talking a 6 mpg drop. Don't think its all winter gas. Is there anyone out there with similar mods or even bigger tires and lift that's getting the same or worse?

 

I still think its a combination of winter gas and your mods, BUT do yourself a favor and try to hand calculate your gas mileage. Some guys have reported that the EVIC calculation has been way off.

You can't compare your 4x4 with mods to your dads 4x2 without mods. Its apples and oranges.

 

My '09 averaged 16 mpg in the summer and 11 mpg in the winter. My new 2500 averages 14 mpg but it only has 250 km on it

 

Short answer: winter gas, cooler temps, larger tires that are heavier and likely have increased rolling resistance, and a heavy front bumper with a winch = lower mileage.

Winter gas: lower mileage from winter gas can happen anywhere that the fuel blend changes for winter. The winter gas blends (also sometimes called oxygenated gas) has less energy per gallon than regular summer blend. So your truck has to burn more of it to perform the same work. A 10-15% drop in fuel economy is not unusual at all just by burning winter gas.

Cooler temps: when it's colder outside, it takes longer for your truck to reach full operating temperature. It's typical for vehicles to run a little rich during warm up, and they ignore feedback from their oxygen sensors. This hurts gas mileage.

Larger, heavier tires: Common sense would indicate that larger tires would equal lower RPMs, giving better fuel economy. This may be true in a steady highway cruise, but around town the opposite is true. Your engine has to work harder to accelerate the truck at a similar rate as before the tire swap because you have effectively made the overall gearing taller. Larger tires weigh more than smaller ones, and the key here is that the tires are considered unsprung weight. Unsprung weight is anything on the truck that is not suspended by the springs...mostly it's the weight of the wheels & tires. Adding 50 pounds of unsprung weight is roughly equivalent to adding 500 pounds to the bed of the truck, in terms of its impact on acceleration, braking, and fuel economy. Additionally, those larger tires likely have a more aggressive tread pattern, which means increased rolling resistance. This means your truck has to work harder to accelerate and maintain speed. This hurts fuel economy.

The bumper and winch. Just taking a stab here, but in the bumper and winch, you could have easily added 500 pounds of weight to the vehicle. All other things being equal, more weight = lower fuel economy.

So really what you're seeing is a combination of factors. Short of returning the truck to stock, about the only thing you can do is to increase your tire pressures to the max sidewall pressure to reduce rolling resistance. But then you might see some increased tire wear on the center portion of the tread, and if you have to replace the tires sooner because of that, you've just killed off any monetary gains from the slightly increased fuel economy.

One other thing you might try: if you only drive around town, try to plan your errands so that you hit the one furthest away first, then work your way back home. Doing that, you're giving your truck more time to reach full operating temperature, and it'll retain more of that heat for the remainder of your errands. But if it's just a back and forth to work scenario, that may not be practical.

 

Thanks for the replys. I understand what ypur saying but it happened before I even did tires so I was putting that out of the cause. I guess ill wait till spring and see if it goes back up.