I used to use shell until my Z started running like crap. They had been sued many time for the additives in their fuel becuase they clog many peoples fuel filters, like it did my new one. It may have been from the MTBE which is sh!t as well. I still wont use Shell even thought they have switched to ethanol. I love 76 it is awsome and they dont use MTBE either. Btw, chevron is sh!t too. Their fuel KILLS GM injectors and they still use MTBE. Thats just my opinion though :) Joseph