I have been noticing recently that my miles per gallon has dropped significantly. I have taken 3 trips from NYC to Chicago in the stinger. The first was in June, and then again in October. In those instances my gas mileage was consistent at 26-27mpg. A couple weeks ago I made the same trip and i was averaging 21-23mpg. Never higher. The same span of highway in both directions. I always use 93 octane. I haven't changed anything on my car since the October trip. What could cause this drastic of a drop? I do have a JB4, intakes and a catback, but all were on my car prior to October and did not seem to affect it then. I disconnected the JB4 for the return trip and it still maintained an average of 22mpg. Any ideas?