I am currently having issues with my gas mileage on my 2004-S60. A month ago replaced my fuel rail pressure sensor, during which time I noticed my gas mileage indicator reading low during acceleration (5-8 mpg). A month later my car is bogging down during acceleration which was diagnosed as a clogged catalytic converter.

I weighted my options, and decided to get it fixed. I get the car back and the car still shows horrible gas mileage. I am going to fill her up tomorrow, and reset my odometer and do my own calculation, but I feel like the computers calculation isnt the problem. Any ideas?


Also, while driving I hear a slight high-pitched scratching that increases and decreases in speed when I increase/decrease my speed......so its something related to the spinning tire. Any ideas?

 

What does the computer say once you get up to speed? Acceleration is always going to give you low MPG's. I don't think it is an accurate way of calculating actual MPG, but it's a good quick reference.

As for the grinding sound, check for binding brake pads or handbrake. Could also be a bad wheel bearing.