The vehicle does have just under 120k miles, was averaging 33 mpg just 8 months ago, and now get 28 mpg. The oil is changed every 3k miles, tires kept at proper psi, just had the transmission serviced.
Loss of fuel mileage, my 2006 vibe has lost on average 5 mpg. on 2006 Pontiac Vibe
have you had a fuel line flush?