The electronic throttle module (ETM) has a higher than normal failure rate. There is a possible extended warranty and/or a software upgrade offered by Volvo for this problem.
Car Problem Reports
Volvo V70 XC Volvo Extends Warranty on ETM Due to High Failure Rate
Volvo V70 XC Problem
Average Mileage: 154,000 mi (136,000 mi - 172,000 mi)
Visitor, 2000 Volvo V70 XC
i throttle the gas and nothing happens..
Visitor, 2001 Volvo V70 XC, 136,000 mi
Going up hills while holding the throttle at a constant pressure, the engine surges, then slows down, over and over and over until the top of the hill. Getting worse...I fear immanent failure soon. And Volvo only will replace if the car is under 10 years old. Which is ludicrous as ALL of these Volvo's will fail.
I had the same problem and on my car the TPS fixed the problem. I found that on my 2001 xc v70 it is hard fixed to the throttle body. I went to a gunk yard and replaced the entire throttle body. That fixed my issue. Rather than spending $200 to $500 I spent $100.