Keep in mind 99 was the first year of the Electronic Throttle System, and thus, is the most problematic. Also, not much DIY here, this is on the VADIS set up. You can diagnose the fault, you can even replace the part, but until the new part is programmed via download by Volvo Cars of North America, it won't work correctly. I won't say don't buy it, because I don't know "this" particular car. I tell my customers to avoid the 99 unless it's love at first sight, and who can argue with that?

Chris