I have been putting this stuff into my fuel tank for about 2 weeks now and have noticed a 15% better fuel economy. Who else has had luck with other additives out there.
What is the name of the product you're using ?
I use a product that adds lubrication to the fuel and increases the cetane rating a little. But i've never compared mileage with and without. I just always use it.
PowerService DieselKleen in a grey jug.
Overall mpg averages have been 49.6 - 52.1 in an old 89 Jetta with 350,000+ miles.
I too use the Grey jug, and the white jug in the winter. It claims to boost cetane by 6 (?) numbers. and add a good amount of lubricating properties for these ULSD days.
If I use anything I use the Stanadyne Performance Formula. I don't really notice a difference so I hardly ever use it. My brother on the other hand noticed a decent increase in mileage using the stuff in his Chevette.
Im not sure what kind of additive you guys are using but i used one that was about 1 litre to every 50 litres of diesel. Your mileage will appear to increase if you don't include the litre of additive which is likely just like diesel.
I sometimes use octane booster in the colder months. Helps with starting.