....a friend of mine, whom I trust to do anything to my cars, told me to put a quart of Dexron tranny fluid in the gas when I fill up my "old" cars('80 Vette, '73 Ranchero, 'bird), every once in awhile. He told me it cleans the valves and cylinders and just makes it run better. He has been doing it the past 15 years or so. Anyone else doing this or heard of it?