If you have carbon build up, there is a gauranteed easy removal of the carbon. First, I must ask you if you have ever pulled the head from and engine with a blown head gasket? If you have, you noticed that the affected cylinders were perfectly clean, steam cleaned!

What you do is connect the windshield washer squirter tube into the intake system. This used to be easy on carburated V-8s. All you had to do is put the washer pump tube into the middle of the carburetor and head for the freeway. Once on the freeway you hit the squirters and watched in the mirror(s). The engine would stumble and miss a little and the biggest brown cloud of junk would be seen behind you. I did this occasionally in my V-8 4X4, and it worked fine. This would certainly be more difficult to do on a FI Volvo engine, but could be done. Oh, yes, an oil change was recommended right after this method. The normal disclaimers apply to this free advice, >;-), I am not responsible for the outcome.

Our three B230FTs usually run just fine on the cheapest stuff. The car with the Turbo+, and the car with the G valve will ping every once in a great while on regular 87 octane. The wife.gov's car runs stock boost and has never pinged on the 87 octane.