One problem related to speed sensor has been reported for the 1999 Volvo V70.
1999 Volvo wagon vxc. Sudden loss of power . The car did not stall except at a stop sign when giving it a lot of gas to get it going. This happened intermittently for two months. Took vehicle to dealership, and they said it would cost $1753. 00 to fix it. The car is out of warranty. They would put in a new steering rod/ front end alignment/ vehicle speed sensor/ throttle body assembly/ an automatic transmission, and drain and refill the coolant.