I have a 2002 XC70 with 72K miles. When I bought the car this summer, I was getting around 20MPG around town. I currently use Royal Purple full syn oil.
It seems that lately my milage is going down, down, down. My instant/average monitor now shows 14.7 MPG. Could the colder weather be affecting my milage. I run medium grade gasoline and every so often I put in a tank of high test, generally BP. Could the cold affect the AWD driveline enough that the oils in there are thicker/stiffer, thus causing my milage to drop? I have not checked my milage against the odometer for 100% accuracy, but rather relying on the digital readout on my dash. My tires are inflated to correct pressure as I check them often. Is there anything I need to check or look for? I am running the same tires since purchase.

 

Last tune up?

 

I got the car this summer and the lady before me had it serviced very, very regularly at Bobby Rahal Volvo in Pittsburgh. I can't tell you the exact mileage however. I have noticed though that just once in a great while, while idling, the idle will drop off very quickly but come right back up to normal RPM's and w/o any aftermath. I do not notice any hesitation on interstate when stepping hard on the gas, nor any problems per se' around town. Does this help?

 

Im just wondering if it is time for a tune up. It usually gets done every 30K.