Diminishing MPG.... why is this happening!?

Hello Tacomians,

As of recently, my MPG has been dreadful. I've got a mostly stock TRD Sport with under 30K on the clock.

Mods are:
Newly purchased 265/70/17 Falken Wildpeaks (at around 34psi)-from stock 265/65/17
Borla Catback Exhaust
K&N "high flow" air filter

I use to average between 18-20mpg per tank but as of these past few months, I've nearly been able to get 14mpg out of a tank. My daily commute has not changed (80/20 city/hwy) and neither has my driving style. If anything I've been more aware of being lighter on the go pedal.


I recently changed out my air intake filter as well as had the stealership do an injector cleaning but still no improvement. My question is what is everyone else getting MPG wise with similar mods and or just bigger tires? Is this considered normal with going up in tire size even though it's minimal?

I understand that bigger tires equal more weight/rolling resistance and therefore worse MPG but I wasn't' expecting such a drastic change. Any and all input is appreciated!!

 

Does California switch to winter blend gas late Fall?

 

16-19mpg. Put some Lucas or Seafoam cleaner in right before your next fill-up. Check out OVTune...it's amazing

 

Winter fuel, seems like it cost's you 1-2 mpg.

 

You stated the answer yourself... yes, that can be the most likley reason.

 

That's a really good question! I honestly have no idea but don't recall having MPG issues in winters past.

 

What are the Wildpeaks SL, or E load range? 46.2, vs 52lb.

 

Winter gas and tires.

Like Spike Lee said about Michael Jordan, it must be the shoes!

 

Yeah, with 30K experience, you know what to expect... if you have a sudden change, and you discount the most recent mods because you can’t link the conditions to the mod, then you may have a serious issue developing given the preventative measures already taken. I’m still thinking it’s your tires...

 

Do you recently enjoy pizza more than salad?

 

I actually lost close to 30lbs recently soo I'm even more upset at the MPG lol

 

I'm also in California, but completely stock drivetrain and tires. I'm not sure if it's the winter fuel blend or the colder start-up temps (probably a combination of both), but I lost about 1-1.5mpg. These trucks take a while to warm up to their preferred operating temperature, and fuel mileage sucks until it gets to that temp. Your new treads aren't helping either.

I've had similar experiences with every vehicle I've owned.

 

My gas mileage actually went up after I put Wildpeaks on, but I am guessing it was because I had an alignment done at the same time, factory alignment was pretty far off with a Toe Out condition

 

The diameter of your new tires is @3.3% larger than your old tires. Have you factored that into your mpg calculation? Addition weight will also play a role...

 

Some tires are better than others. I put on Cooper Discoverer AT3s and lost 2-3 mpg. Actually, I aired down to 30 psi which I think is what really killed it, I’m airing up to 35 psi to see if it improves.

 

hmmmmmm, I have yet to get an alignment..... this may very well be my next move

 

I doubt it’s the tires. I have 295/70/17 STT Pros and a lot of other added weight to the truck and I get 14-16 MPG with stock 4.30 gears.

 

Is not the tires. I went from 265/70/16 (stock on PRO) to 275/65/18 E rated, lifted 3", TRD CAI, oil catch can, 5W-30 oil and in winter I get 2-3 MPG loss. I tried 87, 89, 91 gas and all the same. This gas has soooo much alcohol in it, I may start to drink it.

 

Hell yeah Gene Simmons, post the YouTube vid. I’ll watch

 

I wore out a set of regular AT3's and had no problems getting 24-26mpg. Replaced them with the AT3 4S and I'm living in the 19-20 range (can hit 23 if I try) with noticeably more road noise. I'll surely be going back to the regular AT3's considering I drive a lot.