BG products makes it - you can usually find it at some auto dealer parts counters including Volvo (at somewhat inflated prices). I usually get it at one of the better foreign car parts houses around town for about $16/can.

This stuff was recommended in a Volvo TSB several years ago as a solution to the porous carbon buildup around the injector nozzles in K-jet injected 240s. This was an laternative to the walnut shell media blast technique to clean the intake tract. Seems to work quite well - but - is heavy duty stuff - don't let it sit in the fuel system - use it when you can drive out a tank of gas in a couple of days. Also, schedule it at a time when you are about ready to changer the oil - blowby from this stuff can contaminate the oil, so an oil change and filter are called for. I would also consider changing the fuel filter after use as well. After use, regular (1-2oz/tank) use of the AMSOIL PI seems to keep the FI system clean and running well - especially on the k-jet systems with their mechanical fuel didtributors.