I know this is an old thread, but I have 15 years experience with this product and can tell you this stuff works. I started running it in my 1990 F150 on it's first oil change and every 3rd change since. I ended up replacing the engine with a FRPP crate engine in 2002 after putting 275,000 miles on it. I sold it to a guy wanting it to rebuild for his Bronco. When we opened it up we were both blown away with the condition of the engine. He even remarked that he would believe my if I said it had 75K instead of the 275K it looked so good. Zero wear on piston walls, cam lobes, or anywhere. The only sign at all of it's longevity was a little wear in one of the main bearings. The inside was spotless with no sludge, and truly looked almost new. I can also report that I got about 1.5 mpg increase.
I put it in my sister's 4 banger '86 Mustang that had about 150K on it, while it was running and about 2 seconds after, the idle speed jumped up about 250 rpms. I ended up having to adjust the carb to reset the idle. She also saw an increase in both power and mpg. The darn thing barely had enough power to get up to mom's house on a hill before, after it was a piece of cake. She also went from getting 23 mpg to getting 26 or 27mpg, and it ran much smoother too.
I run it in my Mustang, F150 and both of the Cummins VT555s in my boat, and it really works. I'm told the owner of the company that makes this stuff has a 350 Suburban with 1 million miles on the original engine, and still running strong.
