Looking for a chemical option to soak the upper cylinders to remove carbon.

MMO is not enough. Reaming the glow plug chambers is not enough. Italian tune-ups are not enough.
Need something that will get in every nook and cranny and break down the carbon.

I heard there was a decarbonization made by Mobil and put out by GM that was fantastic for this purpose but I don't think it's made anymore.

What about Seafoam?

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