Lost fuel mileage

I gave a 02 Tacoma V6 4X4 with 4:10 gears. Having issues with fuel mileage I went from 350 miles with full tank. After installing 33X12.50 with 20 inch wheels now for some reason I'm getting 180 - 190 a tank.can someone help me out an maybe guide me to why?
Could this be bad plugs/ wires /or coil packs ?

 

Combination of bigger tires throwing the milage off and bigger heavier tires mean crappier milage.

 

Heavier wheels and tires = additional rotational mass. Also combined with larger diameter tires = less revs per mile.

Those two major variables significantly impact your mpg.

 

I do understand that but I know other trucks other people that have the same truck same wheel setup same tired not having that fuel issue not that bad of a decreased anyways. I'm losing over a hundred and seventy-five miles there's no way I would understand this light for me 30-40 mile decrease

 

You're going further than indicated. The speedo/odo are calibrated for smaller diameter tires.

 

I have the same truck, same gear ratio/engine and 33" tires as well. I get the same miles per tank (190 on a good tank if I'm lucky).

Welcome to the world of 33s on a 1st gen Tacoma

 

And yes it's not quite as bad as you think, your speedo/odometer aren't getting an accurate reading with the larger tires. I think it's something like a 7% difference last time I looked it up, don't quote me on that. But you're getting a few more miles than you think you are, at least.

 

Ok, might be stupid question but can it be recalibrated for larger tires or is there another way to go about that? Again this is the first time I've run into this problem or heard about this much of a fuel loss do to that size increase. I had 32× 11:50 an fuel was fine so I'm lost ‍♂️

 

Slap some 557’s in that bitch

 

It's not Friday yet

 

Here's something you can try. If you have a phone mount, you could use waze, it'll tell you your mph, compare it to what the speedometer says, that'll give you a hint how far off it is.

 

I believe you can recalibrate it, or you can buy a larger speedo gear to account for it.

If you wanna find out the % change in your speed and miles driven, I always use this site when comparing tire/wheel changes.

https://www.rimsntires.com/specspro.jsp

Put your OEM wheel/tire combo in the top left panel, and new wheel/tire combo in the top right panel. Everything below will tell you how your clearance, poke, speed, backspacing, etc changes

 

Plug in factory tire size here then new tire size. It will show a visual of the difference as well as the actual measurements of the 2 sizes. You'll get a percentage difference too. I'm betting there is a 10% difference in diameter. You can multiply the distance the odometer is showing by the percentage to calculate actual distance driven. If it does come up 10% you multilpy by 1.10. If 7% then multiply by 1.07. If your odometer shows 190 miles then if your new tires are 10% larger multiply 190 by 1.10. 190 X 1.10 = 209 miles actually driven.

Your speedometer is off by the same percentage. If the speedo says you're doing 60, then you're actually doing 66. Driving faster hurts fuel mileage too. Especially when you're engine is working harder.

Other factors. A skinny 33" tire doesn't hurt fuel mileage nearly as much as the 12" wide tires you have. A 10" wide 33" tire will be much better. Tread matters. An All Terrain tread has much less rolling resistance than an aggressive mud tire.

Lastly, miles/tank is mostly useless information. You need to figure miles/gallon. And if you never calculated MPG before changing tires you have no baseline to compare it to.