I would say clean your Mass Airflow Sensor (easy to do- youtube it) and while you're at, check to make sure your intake box filter looks good. I would also clean the throttle body and idle air control valve too. I just cleaned my air filter and airflow sensor and my idle is much better (lower RPMs and smoother) and my mpg gauge is saying i should be getting around 390 on a tank (don't know how accurate that is).

What's your tire pressure?

I don’t understand the huge mpg variances, driving style excluded. I got 19+ in my 2015 sr5 and was getting 20+ in my 2017 until I did the lift and the bfgs. Now I get just under 19. Have you tried higher octane fuel?

I agree with mash above. Try cleaning the MAF, replacing o2 sensors and checking gaps on the spark plugs. Also, try pulling negative terminal for a few hours to possibly reset the ecu.

Worth mentioning and I hope no one does this but do you drive with two feet? Left foot resting on brake, right on gas? Ive heard people say "Thats how I was taught to drive."

There is something off. I have a 16 trail with KDSS. Lifted 3.5", 33s at 40 psi, sliders and a steel rear dual swingout and I get 16-17mpg on 87.

I see you calculate by amount of gas and previous milage. I use fulley on my phone to track my gas. Have been for awhile.

Hope this helps and good luck trying to find the problem.

Im new to the 4Runner thing, but my '19 ORP is getting 15.5 ish MPG so far. Wish it did better but that's just what you get I guess. Does anyone know if there is something out there to put a tune on the computer to increase MPG and/or performance?

pretty close to mine

yes, you can do a few things to increase mpgs and also performance. I'm also new to the 4runner thing and have found the performance lacking to say the least. Cold air intake (trd pro, afe, k&n, etc) should give you a slight bump in both areas. Headers, y pipe, and exhaust should also do the same ( keep in mind some of things will make your suv 'illegal' for highway use for emissions). Once you have added some or all of those mods, then something like the URD MAF sensor calibrator will really tune it all together for even better performance and increase in mpgs ( i'm going to try to get a group buy going for it if you're interested). Lastly, you can also add on a pedal commander or sprint booster to give your gas pedal feel alot more responsive instead of the stock sluggishness. I hope that helped a fellow newbie to t4r

I was looking into those things as well. They are on my list of "to-dos" for the truck. But keep me in the loop about the group buy thing. Thanks for looking out!

On my fairly new 2019 TRD Off-Road, I was at 18.1 mpg, then after taking a 300-mile trip mostly on the highway, it went up to 18.6 mpg.

2012 Trail with 97k. Averaging 18.5 with load range E Falken WildPeaks AT3Ws. Seems like our driving styles could be similar as well. I agree with the plug change, and I am going to be doing the same on mine soon. As someone suggested above, you could also have a frozen caliper - it is a fairly common issue. If it is neither of those, I would consider taking it in.

Thanks for all the other ideas everyone.

Air filter is like new. Tires are at about 34 or 35, forgot what i set them at, but it was 2-3 above the door rating, still chilly here in the morning, keeps idiot light at bay from the temp pressure change.

The fluids are good, just bought it from a Honda dealer, and had it Serviced at my local Toyota dealer.

The brake rotors are warped in the front, but I am debating on dealing with it until it needs pads, it's only annoying when medium to hard brake is applied, but when you do the steering wheels shakes.

Guess its plugs and intake, idle, maf, fuel injection cleaning time. Maybe also a fuel filter. Sucks but that's what I get for buying used lol.

No pulleys binding that I can tell, idle is right, engine runs good and strong and smooth. Although I swear the first time I ran the ac for an hour or so, the mpg went UP like 2 mpg, then went back down lol.

Did I mention I hate the nanny HVAC system that wants to control things based on temp settings against my will? I am convinced this is the evil thing killing my mpgs

Those last couple of sentences made.me chuckle!

Good luck, keep us in the loop when you find the culprit.

Clean MAF, replace air filter, reset ECM. I dunno, I get over 20, but I drive a lot of highway. Like 90%. 120k on the 4runner, and oh yeah, the spark plugs are fairly fresh too.

Not sure what could be causing your issue other than that stuff, or it may be just driving conditions.

For instance, I know my wife would never get even a hair over 13-14mpg on mine. That's due to her commuting patterns and driving style mostly.

‘19 Limited Nightshade, 1900 miles, front leveling kit, 265/60R20 KO 2’s & a Magnuson supercharger ... 17.5 to 18.5 mostly rural with some city & hiway. We can’t pump our own gas in Oregon so that’s computer mileage. I have done the math and they’re pretty close.

2015 Trail Prem. with 3 inch lift, 33's and roof rack was getting 17.2 on avg. Just installed the sprint booster on setting green 4 and after 3 tanks, I'm getting 18.2 with no change of driving than before. I was a little shocked at the immediate change in mpg.