I'm having the same issues with my 99 V70 2.4 (P0600, speedo stops working for a sec). But, I also have the P0722 Output Shaft Sensor code. If all of this is going on with a P0722 code, would it be more likely the sensor or ABS module?

This is great info, I'm having the same problem with my 99 V70 with 126K miles. I think it's actually gotten worse over the past month or so. Looks like I'll need to change it soon. Very recently, I can actually see a bit of fog coming out of the vents when I fire up the heater.

Sorry it took so long for me to reply. Replacing the antenna in the steering column solved the issue completely. Thanks so much for the help! It was a relatively easy fix, and I have had no issues since.

I'm having the exact same problem and I'm very happy I found your post! The first thing that came to mind when it started happening was an immobilizer issue, but I was unfamiliar with the system on my own V70. I cleaned the throttle body first just in case, which actually helped with smoothing the i...