If you go to www.toptiergas.com you will find out that some auto mfrs. have put together their requirements for gasoline. Apparently the detergent levels have been falling over the years. They list Gas companies that meet their requirements. Here in the West, we only have Chevron and Shell for a choice. I have been using Chevron in my '87 300E for over 100K miles. I have never had any fuel problems. I still have the original injectors at 200K.
Neil M.