Hi,
I have a 98 S70 GLT (221K) and I'm seeing symptoms similar to yours so I had some questions about your post:
1) The OBDII connector is in the center console and from the video on their website, I see the UltraGauge plugs into it with a wire. Does that mean the lid of the console is always propped up by the plug, with a wire running from there, up the dash and to the display?
2) Do you feel it is necessary to remove the throttle body to clean it properly? I have always just sprayed some cleaner in there and wiped it out with a rag.

Thanks for your reply and the endorsement of UltraGuage. It looks very cool and has a great price.

Regards,
Homer Hegedus
Austin, TX