Trailhunter auxiliary gas tank

[Cordoc]

I recently completed a trip from East TN to WA and points in between. The trip covered 7675 miles over varied terrain and driving conditions including 200+ miles of off road driving some in 4WH and 4WL. The trip began with roughly 2300 miles on my Trailhunter and finished just shy of 10k. I ran the truck across a scale and it was 6660 lbs loaded about 175 lbs below the GVWR. Here is a synopsis with actual data below. Note the truck includes the OEM roof rack and an Alu-cab contour canopy top with roof mounted MaxTrax, otherwise wheels and suspension are stock.

Average: 17.25 mpg
Plains SD, KS, etc. 75-85 mph Speed limit 14-15 mpg
White Rim Trail 2WD, 4WD H & L 12 mpg
Reduced speed and lack of wind 19-20 mpg

In some cases where gas mileage was high it wasn't clear why based on driving conditions. The same is true for some lower mpg results. It's possible the exact gas formula plays a role. Most but not all driving was in ECO mode, but since 4WD kicks it out of this mode I didn't always notice it was off. As others have noted, it is not clear that ECO has a significant effect on highway driving which covered much of this trip.

While the average MPG wasn't as bad as I anticipated based on others comments. The most frustrating thing as that I had to stop for gas at 200-250 miles where I generally drive 300 before stopping. There is one result below at 282 miles in ID where I ran 10-20 miles below what the truck says was empty. According to gallons added there should have been 1.5 gallons or more left so there is a little wiggle room in what "empty" is per the gauge. Nonetheless, it is concerning when you are in remote areas where gas is limited and far between. Needless to say, I would love to have a tank that adds 4-6 gallons to increase the real world range of this truck.

Date	State	Octane	Odometer	Miles	Gallons	MPG
8/30/2025	TN/KY	87	2547	229.3	14.486	15.83
8/30/2025	KY	87	2631	84	4.994	16.82
8/30/2025	MO	87	2896	264.9	15.006	17.65
8/31/2025	IA	87	3138	242.2	14.151	17.12
8/31/2025	SD	87	3397	258.4	14.45	17.88
8/31/2025	SD	87	3633	235.7	15.987	14.74
9/1/2025	SD	87	3830	197.3	12.758	15.46
9/1/2025	ND	87	4077	246.6	13.587	18.15
9/2/2025	ND	87	4252	---	6.202	NF
9/3/2025	ND	87	4414	337.6	12.412	18.14
9/3/2025	ND/MT	87	4597	182.3	11.964	15.24
9/3/2025	MT	87	4851	254.1	14.54	17.48
9/4/2025	MT	87	4958	106.7	6.125	17.42
9/4/2025	MT/ID	87	5154	196.3	9.765	20.10
9/4/2025	ID/WA	87	5290	136	6.704	20.29
9/4/2025	WA	87	5484	194.7	10.308	18.89
9/5/2025	WA	87	5734	249.8	12.604	19.82
9/6/2025	WA	87	5931	196.6	9.928	19.80
9/6/2025	OR/WA	87	6171	240	13.415	17.89
9/6/2025	WA	87	6327	155.5	10.205	15.24
9/7/2025	ID	87	6609	282.1	16.391	17.21
9/8/2025	MT/ID	87	6783	174	11.141	15.62
9/8/2025	ID	87	6923	140	7.605	18.41
9/9/2025	ID/UT	87	7165	242.4	13.579	17.85
9/9/2025	UT	88 No EtOH	7342	177.4	9.264	19.15
9/10/2025	UT	87	7582	239.4	12.653	18.92
9/10/2025	UT	88 No EtOH	7725	142.7	8.811	16.20
9/11/2025	UT	88	7896	171.1	10.268	16.66
9/12/2025	UT	87	8072	176.5	10.803	16.34
9/13/2025	UT	87	8150	77.6	4.01	19.35
9/14/2025	UT/CO	87	8399	248.7	18.755	13.26
9/14/2025	CO	87	8597	198.3	11.434	17.34
9/14/2025	KS	87	8866	269.3	14.817	18.18
9/15/2025	KS	87	9066	199.3	13.368	14.91
9/15/2025	MO	87	9301	235.5	13.435	17.53
9/15/2025	MO	87	9530	229.1	12.523	18.29
9/16/2025	KY/TN	87	9764	233.8	13.922	16.79
9/16/2025	TN	87	9995	230.3	12.474	18.46

Thanks for this, great record keeping.
This is more proof of the problem . A marriage of a hungry power train and a small tank.
I honestly do not think that a replacement tank will ever arrive and that we will have to use portable tanks forever.
Otherwise it is a great truck.

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[mtbocoee]

Prices weren't bad in the Midwest, but not that low. Worst was $4.70 in WA just east of the North Cascades. The entire trip cost $1454 in gas.

 

[TacoFreak]

I honestly do not think that a replacement tank will ever arrive and that we will have to use portable tanks forever.

Yeah, there just isn't a lot of space under there for a larger tank, and portable might end up being our best (only) option.

 

[Pappy]

On the way out from Florida on my trip in June, I bought gas at a Loves' outside Oklahoma City on I-40. Notice the price, I could not believe it!

Suggestion. Get the Loves app. You can save 10 cents/gallon at the pump.

Also get the Pilot/Flying J app. I don't remember if they discount at the pump or not. I just did a 13K mile trip to Canada and Alaska. Loves truck stops were my friend and I would always seek them out.

Third option, though not as generous, is Maverik. They give 3 cents off/gallon.

 

[Pappy]

Yeah, there just isn't a lot of space under there for a larger tank, and portable might end up being our best (only) option.

I think there is a spare tire tank in our future. I certainly hope so. I know of two companies working on it.

 

[TFOUTS]

Suggestion. Get the Loves app. You can save 10 cents/gallon at the pump.

Also get the Pilot/Flying J app. I don't remember if they discount at the pump or not. I just did a 13K mile trip to Canada and Alaska. Loves truck stops were my friend and I would always seek them out.

Third option, though not as generous, is Maverik. They give 3 cents off/gallon.

I have both Loves, Pilot, Circle K, and Maverick. Good deals

 

[mtbocoee]

I had to satisfy my curiosity because I was thinking that the Trailhunter mpg was not significantly different from my 2000 Tundra extended cab with a 4.7l liter V8 that I had taken on previous trips. They only significant mod to this truck is the addition of a Leer fiberglass cap. Payload would be similar if not more because in past years I took a mountain bike and all associated gear and clothing.

Somewhat surprisingly the results are similar. Granted the two trips are not identical, but they do cover quite a bit of common ground though there would have been limited driving in 4WD on last years trip. The Tundra averaged 17.42 mpg over 4158 miles. The data are below:

Date	State	Octane	Odometer	Miles	Gallons	MPG
9/1/2025	KY	87	311948	300.0	17.086	17.56
9/1/2025	MO	87	312260	311.2	17.902	17.38
9/2/2025	KS	87	312505	245.5	14.484	16.95
9/3/2025	KS	87	312625	119.9	7.890	15.20
9/4/2025	KS	87	312807	182.0	10.250	17.76
9/4/2025	CO	85	313026	218.4	13.636	16.02
9/5/2025	CO	85	313295	269.3	13.490	19.96
9/9/2025	UT	85	313611	316.1	19.431	16.27
9/10/2025	UT	85	313791	179.3	10.749	16.68
9/11/2025	AZ	87	314044	---	10.109	NF
9/12/2025	NM	87	314211	420.8	13.367	17.92
9/12/2025	TX	86	314576	364.9	18.285	19.96
9/13/2025	OK	87	314891	314.7	18.194	17.30
9/13/2025	AR	87	315090	199.9	11.642	17.17
9/14/2025	AR	87	315360	269.5	15.520	17.36
9/14/2025	TN	87	315498	138.1	7.780	17.75
9/28/2025	TN	87	315807	308.4	18.888	16.33

It would appear that Toyota managed an engineering marvel in creating a 4 cylinder that equals the gas mileage of their 25 year old V8. To be far, I think the GVWR of these two is similar as the Tacoma has grown to a full size equivalent if compared to 2000 full size pickups.

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