Insanely Low MPG, Can't Get a Clear Answer, PLEASE HELP

Gas tank appeared to be okay visually. We replaced the drive shaft on it upon purchase (point of impact caused a warp), and nothing else underneath seemed off to the naked eye.

 

Might want to look up weight of wheel and tire combo. Guessing 20 inch wheel weighs a ton compared to factory size.

 

Best thing to do to fix your gas mileage is to sell the Tacoma and buy a Prius. I put stock size (265/70/16) AT tires that weigh 6lbs more than the garbage stock tires. Lost 1mpg. It’s a truck

 

You missed the point of the entire post, and I'm not exactly sure what compelled you to comment. No one is expecting or wanting the Tacoma to get spectacular gas mileage. I'm seeking troubleshooting advice to ascertain possible mechanical issues given the current level of performance, which is far below what oversized tires/lift would be expected to create.

 

How do you determine the miles driven per fill up considering the wheel and tire combo are throwing off your milage?

 

Okay, so I actually just did this for the first time, using the link to the tire size converter a previous responder posted. The current tires were 33" which I divided by 26.9" (OEM size) to get 1.23 ... I multiplied this number by the reading on my tripometer upon yesterday's fill up (196) to get 241.08. I divided that number by the gallons it took to fill up (14.4) and got 16.74.

1. Did I do this calculation correctly?
2. The 14.4 gal fueled from bone dry to pump click is troublesome to me. I'm still thinking the gas arm/float/gauge need to be checked out.

 

Mine takes about 15 gallons from when the light comes on.

 

Not sure about 1, even if that explains it re the MPG I still agree #2 is in need of investigation. Your surmise of the cause is probably right from what I've read here, either that or the dented tank I mentioned but it sounds like that's not really feasible

 

Sounds about right. My rough calculations show about 40 miles off per tank.

To me, getting 10-12 mpg out of that truck kind of makes sense.
The wheels look to weight about 35 pounds each.

That combo of lift and wheel/tires surely will kill mpg. I only get around 16mpg combined on my 2015 with 265/70r17 tires and small lift. To get the 16mpg I really need to baby the throttle. I could easily see you truck getting much lower.

 

looks like math solved this problem

 

Roundabout what I came up with too. I believe the tripometer showed either 196 or 198 when I filled up. Then 241.08 was what I got using a formula I found on this forum, so that's 45 miles +/- a couple. Makes me feel a world better about the mileage situation, but I'll be noggin scratching over this gas tank until I have time to check out the arm/float/gauge. Thanks for the feedback, hoss.

 

Seems that way. Until solving one problem made me question something else, lol. But that's how sh*t goes I guess.

 

tbh 20's with 33" tires is lighter than most guys here running 33"s on a 16 wheel so 15mpg seems fine to me.

Edit: So yeah, 33" Ko2's on a 20 inch wheel are only like 5lbs lighter than 33" Ko2's on a 16 inch wheel. But the 20 inch wheel is likely waaaaay heavier than a 16. Gotcha.

 

Thats why I asked that question a few days ago haha. All this advice is great, but no one takes into consideration that at 60mph his speedo is 5 mph off

 

That's not true....

Tires are 57 pounds and wheels are 35 pounds.
Most 16 inch wheels are nowhere close to 35 pounds and many 33 inch tires made for 16 inch wheels are close in weight to the 20 inch tires the OP has on his truck.

 

26.9 or 29.6?

 

THIS!!! That is a heavy ass setup. At least 20 lbs per wheel heavier than my aftermarket wheel and tire combo.

 

Oh shoot, I always figured the alloys wheels were lighter inch for inch than larger tires, especially 10 plys.

 

Just to add to the gas tank size. Even with the needle buried I've never put in more than 18 gallons, usually when the light comes on its a 15gallon fill up.

Most cars when the light comes on that's about a 50ish mile reserve so you are not bone dry id you're going off the light.

 

Adding sidewall to a tire is mostly just adding air space, the bulk of tire weight is in the outer carcass/tread area. Adding size to a rim is adding much heavier metals (even if aluminum alloy or magnesium) in just about any case.