I'd argue this is one heck of an outlier...
In all of my 1st gen tacoma's and 3rd gen 4Runners, I think the best I ever got (stock and modified) was 19.
I will make a correction here. I did not notice until you commented, but I typo'd the number. I meant to type 22.5. You may still be quietly saying "bull****". I am always suspicious of people fuel mileage claims too. It is too easy to get sloppy, or to always round a bit optimistically.
The 22.5 number was attained on the last leg of a 1960 miles trip from Anchorage to Haines (then ferry to Juneau-ferry to Skagway) and Skagway to Anchorage return run with a couple of side trips. Hard to keep accurate note of exact milage of each leg when you are filling from different pumps along the way, but I have gotten very good at topping the tank of very very consistently over the years at different pumps. Final refill was done at the same station and same pump as the initial fill up. My numbers on the various legs on this trip were consistently supported my my OBD2 scanner. I actually just took a few moments and checked the numbers as I still had them recorded (no I am not normally that anal retentive but I remembered where I had recorded these, so I went ahead and looked again, it IS a high number).
Overall fuel mileage for the entire trip was 21.3 Call it 21 'cause I am not gonna claim to be precise enough to confidently call it to the tenth. Before anyone asks, that does not include miles sailed on the ferrys.
I tend to run on cruise control when I can, but in hillier terrain I use my foot since I can consistently drive smoother and gentler than the CC does. The 3.4 just does not have the torque to slog up the hills without surging downshifts that definitely impact economy and also just irritate the hell out of me. On the (good) open road I almost always loaf along at 65-70 mph. On the out of town roads here anything more usually requires more attention and 72 is about all the troopers will let you slide away on as well.
On this particular trip I was running some Michelin 265/75R16 LTX M+S with very very thin tread. Summer time temps in the high 60s to mid 70s. Decent paved road all the way. Traffic was never a significant concern on the empty-ish two lane highways. Fresh air filter, fresh plugs, 10-30 synthetic oil. Well maintained 300K or so on the drivetrain. 20 inch light bar on the front bumper, no other aerodynamic handicaps added to the rig. No AC the entire trip (needed to be recharged). The multi-mode TC was in 2wd all the way. Two people with max of 100 lbs of gear.
The final leg where I attained the 22.5 was done late at night in slightly cooler temps and zero traffic. 90% was long straigh with gentle curves. Gentle altitude gain of about 2000 feet about 3/4 of the way into the 330 mile run, with a loss of about 3000 over the rest of the distance. Obviously there were ups and downs along the way, but few serious grades.
Short story is... Yep, I agree that is excellent fuel mileage for one of the rigs. But i am 100% confident in my numbers.
My more recent trip which yielded an average of 20.5 over about 1000 miles saw some higher temps, more upgrades, some twistier roads and less consistent speeds. Maybe another 100 lbs in the rig over the trip reference previously. A stretch at very low speeds through an active forest fire zone, a bit of unpaved road (150 miles or so), half of which was done in wet and extremely sloppy "greasy" conditions, and heavy rains for the entire second half of the trip. Vehicle in similar proper state of tune but the plugs and filter were not brand new. Also different tires (same size and brand/model, just fresher tread). The unpaved portion of the trip was done in AWD (TC unlocked). The autoclimate control was on almost all the way (AC functioning now). Overall a little more traffic but for the most part that had little effect on the driving speed/style.
The average mileage of 20.5 is based on the entire trip, with initial and final fill done at the same station/same pump. Within the accuracy that I could ascertain, the trip north apparently averaged 21.5 (better road conditions lighter traffic and more consistent speed) and the return trip 19.5 (all of the sloppy wet dirt road AWD distance was on the return trip and , again heavy rain all of the return trip.
The 19-20 is more indicative of my normal highway fuel economy with this rig. But the 22.5 is a number I will confidently stand by for a "best ever".
This rig has become my go to for road trips, over the GF's Subaru which averages 26-27 (never checked or monitored as carefully as I do my rigs) but it has neither the comfort or carrying capacity, is noisier and rougher riding, is just not as much fun and it is definitely lighter duty for using on the less ideal roads. We DID take it all the way from Anchorage to to Dead Horse (and back of course) on a spur of the moment trip though! Also choosing this rig more over my FZJ80 if the road trip is expected to stay on the roads. The '80 surpasses it in almost every way... but at a normal 13 mpg (best of 15.5 but 13 is practically set in stone for this rig after many many miles and measurements)... well, fuel mileage starts to matter more on long road bound outings.
Mark...
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. There have been times when we said good night and she was supposed to go home. I go upstairs to my bedroom with the windows open, and I can hear her blasting her music and idling for quite a bit before she decides to head to her own house. I don't understand teenager logic these days but whatever.
