Thanks for your response.
"Device" might have been a better term to use, although the company says "chip". Supposed to give better performance/mpg. Some people have reported significant improvement, some no change. I don't want to be a victim of the placebo effect, so I like to run several tanks full for a test. Their installation instructions say to splice into the wires in the back of the connector. I am concerned about possible warranty issues, so I want to make it "plug-n-play". Their website is at http://yhst-19807630266082.stores.yahoo.net/
Like I said above, I am a bit skeptical but I try to keep an open mind. It always seems that both sides of an issue like this are usually very passionate about their side. Some will say "works great" and some will say "scam". Neither side is necessarily lying, may just have different observations. So I like to see for myself. Enthusiasts often like to drive 50-100 miles and then draw their conclusions. Such a small data sample is subject to too many variables to be useful. Even 1,000 miles is a small sample but, obviously, much more reliable than 50. I put over 15,000 miles on a device called Platinum Fuel Saver. I got no improvement at all but others have reported good gains. On the other hand, I tried a mod called the Gadgetman Groove on a 94 Ranger and got about 15% better mpg. Same with HHO. Got about 15% better mpg in a 96 Dodge halfton.