[HO455]

A retired GM engineer told me that they had a department at GM that looked into parts and additives like this one during the 70's and 80's when they struggled with emissions. The thought was that they couldn't think of everything and maybe someone would come up with a cheap idea that would save the company millions of dollars or make it easier to meet emission standards. To his knowledge they never found anything that was of any value to them. Over 20 years of testing everything they could find. None even worth 1 mpg difference in a new car. I remember that every time I'm at the parts store looking at all those items claiming to solve my problems. Most of these items only hide symptoms of other problems.