I was told by a friend (don't laugh) that one could clean out the inside of the engine, pistons, oil flow system, etc. by disconnecting all spark plugs, draining the oil, and pouring about a gallon of gasoline into the oil filler spout, and then cranking the engine. he claimed various benefits in doing so, basically more efficiency.
Is this true or BS? I recall a few years ago there was a company called Enginuity that reportedly cleaned the inside of your engine, oil flow system, etc. Any comments? Or should I tell my friend to verify his dosages?
Thanks, Carter