first off... 1995 accord v6 mpg estimates (your mileage may vary by +-%25 or more)17 City, 19 Combined, 23 HwyAssuming you're guesstimating your mpg (it sure looks like you are with 200 and 16) it could very well be 12.5 with no problems with the car.Check air pressure in tires, they should be set no lower than what is stated on the drivers door jamb, and no higher than what is stated on the tire sidewall. The higher the pressure the better MPG, the lower the pressure the better the ride/traction.Is the check engine light on while driving? No? Then chances are it isn't the O2 sensor. You can take the car to your nearest autozone (possibly any large chain auto parts retailer) and they will scan it for you and tell you what the trouble codes are, if any.My guess would be 90% of the mileage differece is the driver. Also get a real MPG number. Fill the tank until the pump clicks off by itself. Drive around 150-200 miles. Fill the tank from the same pump until it clicks off itself. Get the gallons pumped.BTW , '95 accords have a 17 gallon tank.