2011 Tacoma getting bad gas mileage

I have a 2011 6cyc 4.0. About two months ago I was getting around 300 miles a tank so about 16.6 mpg which isn’t good but I do have 285/75/16 10ply tires and a full metal rear bumper. Now I am receiving about 12 mpg. I did install the “Pedal Commander” but even with it turned off I still get the same gas mileage. Is winter gas that bad? I live in Utah so it does get cold but it seems to be getting worse as the weather warms up.
Anything helps! thank you

 

Any check engine light on? How are you on maintenance (spark plugs, air filter, oil change, etc)? I see you have a K&N air filter so you may check and make sure your Mass Airflow sensor and throttle body aren't dirty.

 

No check engine or any lights on, I checked yesterday and I was about a quart low on oil so I topped it off I’m guessing that could have something to do with it. I’m about 1000 miles till next change but I was in moab recently and when you’re on those steep angles it burns oil but it was getting bad mileage before moab. New air filter, I have new spark plugs on the way. but I’ll give the mass Airflow and throttle body a look today.
Thank you!

 

How many miles are on the truck? How many miles are on the plUGs? When was the last time the throttle body was cleaned? When was the last time the MAF sensor was cleaned? Do you have any exhaust leaks? Do you add anything like Chevron techron to the gas? Do you do a lot of idling?

All of these things can result in a loss of milage. Except adding the techron I suppose. Plugs are spec'd to be replaced every 30k.

They make specific cleaners for the MAF and throttle body, fyi. You will notice a difference when they're cleaned. If you clean these and don't disconnect the battery, the engine will idle high when started. Then it'll start dropping the rpm. Stop, check, repeat, until normal idle is reached.

Be very gentle with the uvula thing on the MAF and the butterfly on the TB. The first is fragile. The second, gear driven. You don't wanna strip those... Spray the MAF only. I use a Qtip inside the TB to clean the tight spots.

If you got a wally world nearby, both can be had there. AND, 2- 10 gallon treated techron bottles are cheaper than 1- 20 gallon bottle at my local auto parts stores. YMMV on that one tho.

Good luck

 

Truck has 84000, new iridium plugs, I cleaned the TB and MAF both were dirty, now that they are clean I’m getting about 12.3mpg instead of 11.1 which is slightly better but I don’t know what’s happening. 2 months ago I was getting about 16-18. I also did one of those techron treatments yesterday and made a trip out to Idaho so I burned it all in one run.

thank you all again for the help!

 

Are those new tires? If yes, what size did you have before? A larger outside diameter tire will throw off the odometer reading; you will travel farther then what the odometer reads. Using a GPS unit I calculated a 5% variance on my Taco; thus, I multiply my odometer/trip reading by 1.05 to view my actual mileage, and calculate my mpg accordingly. Other than that, I would blame part of that drop to higher alcohol content in winter gas. What is a pedal commander? Does it involve removing vacuum lines? Speaking of which, replace the PCV valve, cheap and simple and about due for replacement anyways if it hasn't been replaced.

 

Tires have about 10000-12000 miles on them but it’s only been the last 2000 it’s been getting bad mileage

 

Shitty gas is my bet,yes winter gas is crap.

 

vvti filters are another possibility . do you feel a loss in power ?

 

Bad gas being dumped on market is likely a contributor. Try again in July.

 

Yea I definitely feel a loss in power.

 

FWIW, the iridium plugs have been known for causing issues in the 1GR-FE engine.

Just for grins....you could try a set of NGK copper plugs. See if the mpg recovers.

 

Dude. Same here. Although I've NEVER got 300 miles on a tank. Never. I was in Cedar city this weekend, only used chevron or Maverik gas, but got the word fuel mileage ever on my way home to Vegas.

I just added new 285/70/17 MT tires with less than 500 miles on them, so they're definitely not helping.. I'm barely getting around 200 miles per tank. So that's like 12 mpg. I also have a steel front bumper, lca skids, and sliders, but no crazy skids under the entire frame.

I'm at 125k miles.. but I've recently changed all the plugs, greased the driveline, changed ALLLL the lubes, diff lubes, etc. Cleaned the MAF.

I did not clean the throttle body, based on reading other reports here, but maybe I should have. I'm probably due for a new fuel filter. The last 8 months or so my truck does seem to run rich and smell more than ever before. No codes, no CEL

 

Yeah mine was dirty as hell, but after all that I got 12 instead of 10. But I’m definitely loosing power which is concerning

 

You cleaned the Throttle body or replaced the Fuel filter? I'm thinking at 125k a new fuel filter couldn't hurt, and that's next on my list. I read a lot of back and forth here about whether to clean the throttle body or not. Lots of varying opinions and such about it, and if it'll help, or if the engine is "comfy" how it is and cleaning it back to new will throw a wrench in everything else that's since adjusted, worn-in, etc. If that makes sense.

Maybe I'll do research on it again and possibly clean the TB. Also thinking about replacing the MAF. I've cleaned it several times, and I'm not getting any codes or errors, but there's gotta be a reason it's running rich and getting such poor mileage. I also replaced the gas cap with one from the dealership, not a cheapy on Amazon. It wasn't the same as the original, but close.

Ever put seafoam through the system?

 

I’m now getting a check engine light. P0022 Intake Camshaft

 

Maybe you did some engine damage wheeling with the truck low on oil. Intake camshaft code could be an oiling issue to the VVTI actuators.
This may help

P0022 OBD-II Trouble Code: Camshaft Position A - Timing Over-Retarded (Bank 2) | Autoblog

 

Just to clarify for OP, the issue it causes is often a drop of 2 or more mpgs. Sorry to say, but good chance you bought the wrong plugs for it unfortunately. I was going to get iridium for mine but if you search there's a surprising amount of people reporting a drop in mpgs for the 4.0L.