A little over a year ago Amsoil had an article about 5-20W on their web page. They warned against Ford and Honda owners using 5-20W. They stated something about the auto companies making the switch to save gas mileage in the mass amount of vehicles they sell every year. I can't find the article now. Is it gone? What happened? After reading the article I convinced my bro. to stop using 5-20W in his stang. Can anyone shed some light on this?