Years ago I tried a product called Tufoil in a Toyota Corolla station wagon that I had bought used. The car would make some chatter at start-up but then would run really good, and did not smoke or burn oil. Afer I tried Tufoil in it, the chatter seemed to stop at start-up. I used Tufoil for several years, but I became nervous because I heard that PTFE should not be used in engines. Many companies that make oil supplements have been fined by the federal government, but as far as I can determine the company that makes Tufoil has never been fined. Tufoil has been around for something like thirty years now. Has anybody ever tested Tufoil?