crappy gas mileage

I just bought a 2010 manual PreRunner 2.7 access cab with 32,000 miles from carmax ($20,500). I have filled the tank twice in the first 10 days and am getting horrible gas mileage, 17.9 mpg first fill and 16.5 second (driving like an old lady). I have not sold my 1999 extended cab 2.4 SR5 with 210,000 miles yet which i bought new in 99 for $15,500 and gets between 20 and 27 mpg no matter how I drive. I have done all repairs (very few) and maintenance to my 99 and cant cant imagine what would cause such poor gas mileage on the new taco with such low mileage.I have read the threads on tweaking mileage but this is something greater than getting better mpg. is it because it wasn't driven enough? Would like to hear your thoughts. Love both trucks, hate to let go of the 99, I use it for construction and after 15 years it is ready for an easier life....

 

I have the 2012 Prerunner 2.7L engine Automatic with 19,000 miles and I average roughly 20.3 MPG driving mostly stop and go traffic. I have not made any road trips yet. I don't hot rod it, but do not drive like an old lady either.

 

I have a 2011 2.7 AC 4x4

18-20 mpg

Not going to get much better...It's a rolling brick

 

I have 2009 double cad 4.0 and gets 21-23 high way and city combined
Use Shell gasoline as it has less of that crappy ethanol than other brands.
Also you will get better mileage on the 89

 

How are you calculating milage? Only reliable way is odometer reading difference between fillups divided by the gallons in the second fill. Don't rely on the fuel gauge divisions (you probably know this already from your prev truck).

What size tires are on the truck? Stock is either P245/75-16 or P265/70-16, both 31" OD. If the previous owner installed larger tires, you will have to account for the odometer error (gain about 1 mpg). If the tires are heavier LT instead of P-metric, you will lose about 1 mpg in the city.

The rear diff oil and transmission oil should be changed at 30,000 mi. Depending on the year, the maintenance booklet can be less-than-strict about it in the wording. Unless the truck came with maintenance receipts that shows the oils were changed, change them. May be worth another 1 mpg.

 

If you are fairly sure nothing is slowing your roll (hanging caliper, axle issue) how much time are you idling? Long idles, whether at stop lights or the nature of the way you use your truck will seriously ding your MPG performance.

 

I am calculating the mileage by dividing the gallons in to the miles and I brim fill
the tank when checking

 

Not a good idea.

 

Fill up til it shuts off ,it allows for expansion.

 

Could you be having a problem with the odometer?
I have an 2014 TRD Offroad 4x4 V6 and I am almost getting that milage.

 

Or oversize tires - they reduce your miles on your trip/odometer because they cover more distance per revolution than factory. That would account for a couple points in the mpg measurement.