Gas mileage dropped drastically

I have a 2010 trd rock warrior with 3in lift in the front and 4in lift in the rear. I have camburg ucas and am running 295/70/17 for tires I have had this size on the truck for 4 years. I just put new tires on that are the same size but 7lbs heavier then the last set I used to get 330 miles to a tank of gas now I'm getting around 211 miles to a tank. What could cause this to drop so much? Like I said before I have been running this size for 4 years and never noticed a drop in mileage. Also when I'm in 4hi and i get on the throttle it pulls hard right do you all think? An help is appreciated

 

Did you go from a AT tire to a MT tire?

 

Also did brand tire might be as much as a .75” difference in height or width. But that is a lot

 

Gas mileage hand calculated before and after?

 

Both are AT and the new size is I alittle bit taller but same width. I was noticing the gas mileage dropping before I started looking at new tires in November and just did a trip to Kentucky and realized how bad it really got. not sure why

 

What air pressure are you running? I noticed with mine when I run at 35psi I get 12mpg if I run at 50psi I get 14.7mpg

 

So the tires are a red herring? This started before tires.

Air filter. Hanging brakes, need tune up....

 

I run 44 psi and have been for years and have never had this problem before and brakes are damn neer brand new

 

I just put a new air filter in until I could clean the k n filter was able to look at one brake caliper but didn't notice it hanging up it feels like somthing is going on in the front diff but not sure. Could plugs and wires really cause gas mileage to drop that much. The last time they were changed was at 100k now it's at 170k.

 

Checked for dragging brake calipers, check air filters, clean the maf sensor, throttle body, and change spark plugs. Winter gas blend will also hurt your MPG also, but 211 is really bad. I get 300 per tank but that's running on fumes and i'm shitting a brick trying to find the nearest gas station

 

Front diff

 

I will try cleaning the maf sensor after work today and I'll check the plugs. I was thinking of the front diff because at one point it was almost out of fluid and now it feels like it might be binding in a certain spot but I could be wrong

 

I used to get 330 to 310 depending on how I drive it that's why im not sure I'll definitely look at what you suggested. I did just put a new air filter in on sunday

 

I forgot to put in the original part of the post that when I'm doing 70mph down a hill and I let off the throttle the truck is doing 60 before I get to the bottom

 

Depending on the decline, it sounds like something is dragging. Diff possibly. Get a infrared thermometer and check your rotars after a drive. They should all be around the same temp.

 

I am having the same exact issue. I was averaging 300 - 320 miles a tank now with new tires I am under 200.. 9.8 - 10.6 mpg. I have a similar setup. Went from toyo open country mt 33x12.50r20 to Atturo trail blade MT 33x12.50r20 lt. The Atturos are lighter as well. Been a pretty dramatic drop.