I have been researching alot about Amsoil and today I placed an order for 2 gallons. My question is this...This spring I ran Sea-Foam to decarb. Since then I have been using Star-Tron ethanol treatment with each fill up. Some dont think the ST will clean carbon but if you read about it it will. My HPDI does not smoke much anymore on start up which is a sign to me that the carbon has been cleaned out. Should I decarb again before I switch to the Amsoil or will the cleaning agents take care of any carbon that may be left?