Re: ATF in gasoline?
I've heard of mixing ATF in fuel, but only in older cars, like your 1977 MB. I've also heard of pouring it (SLOWLY) down the carb while the engine is running, or letting it slowly get sucked into a vacuum line. This can really clean your combustion chambers, but you need to be really careful about hydrolock.
I think one of the reasons it was used in the past was because 1) there were no good alternatives and 2) older cars need more of this type of cleaning than newer cars. I certainly wouldn't use it now, and certainly not on your modern Porsche.
On the other hand, adding a bottle of Techron or Gumout Regane to the tank now and then won't hurt anything. I think some cheap gas stations don't put much of these cleaners in, or they use the weaker ones, barely meeting the minimum requirements or even not meeting them (to save money). Porsche even recommends Techron. To be sure, some cars need it more than others. I've had a couple of cars that really responded well to these cleaners, while on others, it seems to make no difference at all.
If you car really has a problem with gummed up combustion chambers, a product like SeaFoam, or even distilled water, would be a better choice than ATF. But I seriously doubt your modern Porsche needs this. I did it on my 993, but I think my combustion chambers were pretty carbon fouled. It made a big difference.
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