I've been having issues with my 01' WS6. Lack of power, check engine light coming on-finally replaced an oxygen sensor so no more check engine light. Is the lack of power the ethanol gas (I do use super). Found a source for 87 octane no ethanol gas. Am I better off with that or super 10 % ethanol. The car does sit, especially during the winter and I know the ethanol breaks down, but is the 87 octane enough?