I know the gas milage on S90's isnt the greatest due to their heavy weight, but i want to know why mine is so BAD. I searched on different websites trying to find aconsistant number but they are all different, some say 20/23, others say 15/20 i have no clue.I have used a little over a quater of a tank this weekand gone a whoping 98.4 miles. Can someone please tell me what is wrong? Is my mass air sensor messed up? any advice is awesome.

 

The official EPA estimates for the vehicle were 18/25 for a combined average of 20. As you may know, as of 2008 all new cars will be tested on new standards to give a more "realistic" mpg. New estimates (available at fueleconomy.gov) that factor in the new standards are now 16/23 combined 18 mpg. I checked and found that your car has a 20.3 gallon tank.Keep in mind that with the cooler weather, we are starting to see reformulated gas (winter blend) which is going to take a chunk out of your mileage. Depending on your how much stop and go driving you are doing, I would say everything sounds normal. I would fill up with gas and then keep tabs on you mileage between fills. Thats the most accurate way of knowing your mpg.

For tips on getting better mileage, LoveMyS60 has a great writeup in one of the S60 threads.

edit: A few other notes. Your mileage can be affected if you have been driving in any kind of wind/rain. Also check your tire pressure. Keeping it at least 35psi.