Getting far fewer miles on a full tank - ideas?

Hey all, brand new member here!

I'm the owner of a 2014 Tundra CrewMax. I'm not really a knowledgeable on vehicles but in looking through the threads here for advice I figured you all might have an idea. I can change a headlight or a cabin air filter, but otherwise I'm pretty useless!

Recently I've noticed recently that a full tank is only netting me about 240 miles as opposed to the 295 that I used to get. I tried a fuel injector about a month ago (never done it before - bad, I know!) when I noticed I was getting about 255 miles a tank. Seems to have just started in the last 12 months. The truck has about 110k on it.

Any ideas or help would be GREATLY (especially with the cost of fuel) APPRECIATED!

 

You can try replacing the spark plugs it could coincide with your issues and probably due at that mileage

 

Anything change recently? New tires, added weight, driving faster or harder, running rougher, more AC?

 

Where are you located? Lots of idle/warm-up time during the winter?

 

Are you up to date on maintenance? Plugs are due for sure. Check your filters and you are due for fluids and other items at the age and miles. Winter gas causes MPG loss and ANY idling will kill your MPG for the tank. Warming up the truck every day for 5-10 minutes will easily drop the tank average MPG by several points.

 

Welcome from LA (Lower Alabama)! I would start with the plugs and any other maintenance items that are behind.

 

Have you actually hand calculated your mpg though? You say your tank mileage is going down but what about actual mpg. That's where you'll know if there's an issue or not.

Also, any recent change or disconnection of your battery?

 

Like everyone has said, any changes in driving habits or mods like lift and tires recently?

You are due for plugs, and fluids, they help.
Good fuel injector cleaning like Lucas can't hurt.
Remote start and idling CRUSH mgp in our trucks.

Summer fuel blend will help some depending on where you live.

After my new tires I am getting 8-9mpg around town.
It S.U.C.K.S.
Especially with gas rising like it's on viagra!
Just saw $4.29 for regular at my local station lastnight
That's almost $89 to fill up from E, which gets me about 180-200 or so miles lol.

 

Try a different gas station if you haven't already.

 

Welcome from NY.

 

Thanks so much all!

I'll definitely look into the spark plugs. What is the rate for that service, if you don't mind me asking. We live in SoCal so no real need to idle and warm up. I had Toyota do a full maintenance at 100k miles so I'll have to double check.

Thanks so much, all!

 

I think toyota recommends the plugs at 120k so they probably wouldnt have done it at 100k.

 

Only 4.29 ? It’s $6 here !

 

Clean mass air flow sensor.

 

Plugs are easy DIY . You tube it, they are about $80 from Napa Auto
Lucas Fuel injector cleaner

 

Are you really only getting 200 miles out of a tank of gas ?

 

Yea, I'm lucky I live in a semi rational American state.
If gas was as high here as it is in some crazy places there would be total chaos and war.
We will not stand for that outrageous tax theft bs here.

 

Yup sure am.

Average 9mpg or so unloaded around town which is 90+% of my driving working from home.
Only partial hwy driving I get is when I go far out to rural areas fishing on Sundays sometimes.

I have had to switch to driving like an old man which SUCKS and barely even makes any difference.

My truck is also one of the bad ones with low stock mpg before I even modified it.
I regret getting these new E rated 34" tires but I'm stuck with them now and need the protection they provide compared to weak ass P rated tires.

I have tried to discuss possible issues but anytime anyone mentions mpg being low around here it's like crocs waiting for the wildebeests to cross the river.

Something mysterious and unusual is going on with my truck but nobody knows or cares but me.

 

We just roll over and take it here in California. There is no lack of cars on the road here , all day every day .

 

Nothing Mysterious going on. Heavy 34” tires and city driving in a thirsty truck will yield poor mileage. “Spirited” driving will also crater MPG’s. Driving like a Grampa will help improve them (where’s the fun in that?). Your Speedo and odo are off by around 6% so your getting better than you think by hand calculations if your not considering that. Truck is a 2014, there’s a chance that some maintenance items could help improve MPG’s.

 

We drink 3 starbucks a day , drive big SUVs and trucks , toy haulers and dirt bikes we only use twice a year and buy million dollar tract homes built on top of each other , and let homeless shoot up and deficate in our front yards . $6 gas is childs play !

 

Thank you for the feedback.
I don't think the 6% difference is even noticeable.
Thats .5mpg and 10 mile distance I think?

It is very mysterious compared to others on this site.
People with higher lifts, more weight onboard, and larger tires claim to be getting better mpg than I am.

The truck runs fine and has 78k miles now. Bought it with around 53k miles all stock, ran fine.
Even stock I could not get more than 14city/16hwy mpg.
3" Bilstein Lift took me to 11city/14hwy.
34" (275-65R20) E rated Falken Wildpeak AT3W's took me to 8-9city/12-13hwy.

I do need to get the difs etc fluid changed.
Also brake fluid and coolant.
Not sure how much that would help.
Also my driver side timing chain tensioner is F'd.
Rattles way worse than any diesel lol.

Really sucks right now and I may even pull these otherwise great tires and try to sell them for a loss.
But I prefer the E rated tires for trouble free driving and low air beach driving on vacation.

 

Disconnect the battery and reset the MTE meter, hand calculate your mileage the next 5, 6,7,8 tanks. and then start with maintenance items. Start with doing things that are free .

 

Already pulled the battery when I switched tires, and again recently for something unrelated.

I need to search out the actual calculations used to figure out my correct numbers but I highly doubt they are off enough to make the situation significantly better.

 

OK, sorry I missed that , I know I have a correction chart somewhere saved on my computer.

 

Having a bad timing chain tensioner at 78K miles seems very odd to me. Are you sure it's not engine spark-knocks you're hearing?...would help explain a low octane or other fuel related / firing problem.

Edit: I have a 2016 Crewmax 4X4 with a cap, wench, and running 295/70-R18s E-rated Coopers (34" OD). I get about 11-12 MPG city driving.

 

No worries, I did not mention it here in this thread.

I just found and did the calculations using stock tire manufacture specs and new tires specs.

My mileage is off by 9-10 miles.
My mpg is off by about .76

So I am actually getting about 190 miles till the gas light is on strictly city driving (about 20-21 gallons fillup in my tiny 26 gallon tank)
Mpg is 9.8

Still really awful and lower than several others claims with 35" tires, bigger lifts, and added weight like armor and bumpers etc.
Maybe they are wrong, or lying idk.

 

I just switched (in stock size) my winter tires , back to stock tires, hand calculated mpg is up 2. So maybe the tires are dragging the mileage down to rock bottom, rolling resistance and weight? Can you get your hands on some stock sized ,P rated tires to see if that boosts mpg's back up?

 

I am sure.
Engine runs fine otherwise, no leaks, minor startup smoke (TRD dual exhaust) no CEL, nothing that would indicate a major problem.
I have listened to the motor closely and investigated online and videos and this has to be the problem.

Some Tundra's are known for this like the cam tower seal leak.
DS timing chain tensioner is not holding pressure so it's loose and flapping around.
Really bad on cold start mostly goes away once warm, but comes and goes off and on at idle, but never as loud as initial cold start warm up.

I got F'd and did not hear it when I bought the truck until it was way to late.
They may have put in heavier oil or something else to quiet it down and I was overly excited to find my exact dream truck in 99% condition in my price range with 1 owner all stock at a fair price in Feb 2019.
I did not buy any warranty from Carmaxrip-off.

Now I have to eat the $2k+ repair at some point but I have been putting it off due to not wanting someone to do open heart surgery on my otherwise perfect engine, and finances for the cost of the work.
I also have not seen anyone have an engine failure due to this yet.

I even drove from DC to Savanah GA on a weeks vacation last year and have been on the beach on OBX twice for a weeks vacation with no issues (yet).

Working from home since March 2020 I also don't drive much now except on weekends to go fishing or vacation trips other then grocery store and what not each week.

 

New 34" tires caused the drop from 11mpg city to 9mpg city.
I went from original size Yoko Geo AT P rated tires to these 275/65R20 E rated Falken Wildpeak AT3W's on 46lbs of air.

I did keep my stock tires as they are like 60% tread still, but suck ass in every conceivable way.

Some one else mentioned rolling resistance could be an issue, and that I should go with a wider tire (which I could not at the time due to space to the UCA on stock 20" wheels)
Now I have Spidertrax 1.25 spacers, but still have the dumbass narrow 8" wide factory 20" wheels so I can't really safely go much wider with these.
I was trying to avoid spending another $1800 on new 20x9 or 10 wheels with +20 offset.
These tires (that I initially did not want) cost me $1400 as it was lol.

Side note, on stock tires my speedo read HIGH compared to google navi on my phone.
About 3mph or so.
My speedo showed I was going 50mph, google navi said 47mph.

Now it reads dead on and over about 50mph it starts to read LOW about 1mph and gets worse the faster I go, 75mph on speedo is showing about 2-3mph faster on google navi

My truck is special