if you're questioning wether your car is getting adequate gas mileage please state it in terms of MPG. To do this fill your car up until the tap stops itself. reset the trip odometer and then drive until you need feel you need gas again. Fill up the car, and then DIVIDE the miles on the trip OVER the gallons it takes to fill the car- telling us you're getting a range of 270 is useless, especially recognizing the large fuel reservoir of the accord.

Did you reset the CEL yet? (use a code reader/disconnect negative on the battery for a while) and make sure it is off when starting the car the first time afterwards--see if it comes back on after driving a little.

MAKE SURE YOU HAVE YOUR RADIO CODE IN HAND IF YOU PULL THE BATTERY-- it might be a pita to get if you don't have it already.