Tennessee. Everything-mechanic for hire. Honestly I haven't touched a Volvo since the dealer.
But they're typically pretty easy to work on, and I'm happy to give more specific advice if needed. E.g. it's making 'x' noise or 'y' part doesn't work or 'b' part is doing 's' or whateverthehell.
You'll probably be describing a common problem. Hopefully any more complex problems that I've had to deal with on those are not going to be a factor. Stuff like random drivability issues, often related to the throttle or the ECM/ETM software...like I said, check the warranty history. If everything in hunky-dory at the moment, let it be...don't go in and ask for the latest ECM flash (also it'll cost money now; throttle warranty was ten years). But it'd be nice to know the last time it was at the dealer, and when the last throttle repair was done.
I was working at the dealer when the very first S70's were starting to run out the ten year warranty (S70 was a 98-99 'refresh' for the 850, utilizing TBW) and the 99 S80's were coming up. They did everything to deny any more claims. I'd have severe surging issues where I KNEW the throttle was bad, but if it passed their dumbass potentiometer quick-test...update software...sell a cleaning...it'd be back.
If you finally did get a legit claim that they might authorize (throttle had a more easily demonstrable fault than 'it doesn't work right sometimes.')...you had to do a checklist on the car, basically. Stuff like a weak battery, any voltage drop from cables (if it wasn't an amount of real concern, I lied), high crankcase pressure. Nope, no warranty throttle for you, one of these other issues must be causing it.
Anyhow, they were still releasing ETM and ECM (flashed as a package) software updates in like '06 or '07. So if it went into the dealer with a throttle complaint, the later it went in, the better the software should be.
I don't know that every car had throttle problems, btw. I think most of them did, or at least were sensitive to needing cleanings. I will say, now that I think of it...I seemed to do MUCH more ETM work on NA cars. There may be something about the boost pressure on the blade? Or the oilier intake charge? Who knows. Something seemed to make them act better on turbo cars...ooh wait, brainfart...your car might have the later style throttle, like IIRC all S60's. It's fairly small with all the guts on one side, and they are FAR better. That would be a Bosch unit.
If it's the one with a big aluminum slab coming off of either size, like some kind of retarded miniature Holly Dominator...That's Magneti Marelli. You don't want that.
Wait, what was this point about again? 😕
Fucking S80's make me ADD with all their issues.