This time on the truck. After I treated the bike a couple of years ago, it steadied down to a stable two miles-per-gallon gain and has kept with that ever since*. So I finally decided to use it on the truck, and ordered a standard kit for my engine size. Changed the oil & filter last week, and treated the engine Tuesday, which was the first chance I had to do it.
'Chance to do it' because, immediately after putting it in, you need to drive. I'd originally planned to do it Friday, because I'd planned to head down to Texas to visit friends; schedule went to hell at work and that went out the window, so, not knowing when I would be able to make the trip, went ahead and did it.
The treatment is simple: shake the hell out of the stuff, put the gas treatment can in the tank, then add the main can to the crankcase, then drive. Best method is to use a funnel to add it through the dipstick tube while the engine is running, other is to dump it in the oil filler port and immediately start the engine. I'd planned to put it in the dipstick tube since, when I got a funnel for adding oil a while back, I got one that had a detachable extension for adding transmission fluid, etc., that would work perfectly. Except(you know what's coming, don't you?) that, despite having put the @_!*#^& extension where it wouldn't get lost, it wasn't there. Or anywhere else. So after ten minutes of asking the dog, the air and deity "WHERE THE HELL IS IT?!?", I gave up and used the other method. The engine was warmed up from running to the post office, so shook the stuff up, poured it in and immediately started up, then started driving.
I have to note, did the gas treatment a bit differently from the instructions. The sheet said to add it to "1/4 tank or less" so it gets sucked into the top end during the driving. Well, the instructions also said to drive at least 100 miles. My truck currently gets about 25-28 mpg highway, which means 1/4 tank would end the trip with me pulling out a gas can to get started again, so I started with a little over, six gallons or(I think) a bit less, drove a bit over 100 miles for the initial treatment, then continued to drive over the last couple of days to run the gas as low as I dared( I HATE running out of gas) to get as much of it through as possible. I tanked up this morning; the book says it's a 16-gallon tank and it took 15.25 gallons, so I think that should do it(I've never let it get nearly that low before).
So now it's use the tripmeter to keep track of mileage for the next while, and see how much/if it helps. I think it will, definitely did on the bike, and an extra 2mpg would be very nice right now.