At present I am doing a test on a product called Ethos FR. It is a fuel reformulator, made of special esters.
The claim- Increass fuel mileage 9-19%
Reduce emissions 30-40 %
Increass smoothnes and performance.
Will clean the fuel system and engine.
test car- 2002 4x4 dodge dakota 3.9l quad. I have checked the mileage on this truck since I have owned it. Average out here in the country is 16.5mpg.
highway best was 19.4mpg.

The co. says it has been suppling this to the US Army for some time now. Also large truck fleets and exporting it to China by the ship load.
I started the test on my last fill up and won't know until Friday what results I got. i put it in my oil and my gas, I can say that the truck feels more pep pee.
And the gas gauge has not dropped as usual. But I don't give much creedance to that. I need real #s, miles driven and fuel used.
I will keep you all posted.

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Stable:
1973 450sl
1978 red diamond ice vette
1975 steel blue convertable vette
2002 steel blue dakota quad.