A slightly different point of view
Back in the middle '60s, when I was working my way through grad school doing tune-ups part time, it became clear that the then new Porsche 911 model had a propensity for plug fouling in traffic almost as bad as the Ferraris of the late '50s, and that "Polish" (to mention my Silesian ancestors) tune-ups were an excellent solution, if and only if they were done right. It seemed important not to go out and just put the pedal to the metal to run the engine suddenly under maximum load in a high gear, but rather, to warm up the carbon deposits gradually by easing up to and holding somewhere around 5000 rpm (red-line 6800 on those) for several miles in 3rd; otherwise the deposits would bake into a ceramic-like coating and the only solution would be new plugs, because even the standard Porsche sand blast machine wouldn't touch it.
I believe a bit farther north in Minnesota (up on the Iron Range) one of my colleagues with a Norwegian name called this a "Finnish" tune-up in those days.
Late addendum: Porsche was adamant that those motors should never be taken over 5000 revs when not under load, and then only when necessary to check the ignition timing (which was to be done at full advance).
Last edited by Fimum Fit; 09-26-2002 at 11:01 AM.