been riding daily to and from work for the past couple of months, racking up miles pretty quickly. 6k mile service is overdue

With mostly freeway riding I get 35mpg, and mixed city/hwy I get around 30mpg, or around 120 miles when the light comes on.
Lately gas prices have been outrageous ($3.89 for 92 octane) so it's costly nearly $16 to fill the tank...used to be no more than $9. But still better than the $52 to fill the 911 with 1/4 tank left