From my experience working at a used car lot seeing cars come in with the throttle bodies all black and gummed up, running atleast mid grade is better then regular. I would clean the tb completely and always run mid grade in them and they never get gummed even after 20K miles. Even tho most cars are tuned for reg, some of them will run better and more efficient with mid grade or even premium. My G6 GT was tuned for reg (stated in the owners manual) but gets better mpg with premium with a noticable performance gain. I run mid in everything but my bike which calls for premium from big name stations mostly exxon.

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No more ranger. Traded in