ARCO gas made me lose 5 mpg!?

brucelidat

So I usually get don't get Arco gas but it was on my way and inexpensive so I got some the other day. Now I usually get abou 19-21 mpg, but on this last tank with Arco, I was only getting like 14.5 or so. So can it really have been that poor quality of gas this time that I lost so much mileage or should I be checking for a leak or something? I did not drive any differently, more aggressive or in more traffic than normal during this. I have gotten Arco occasionally before and never noticed this before. So is Arco really that bad and I never noticed or was this just a really bad batch? Also, there was some water dripping underneath my car,but I think a little water/condensation is normal right? It wasn't gas.

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