Viewer-submitted questions for The Car Doctor: Q: I perform routine maintenance on my family’s cars and just want to know your thoughts on Marvel Mystery Oil as both a fuel additive and oil additive.

John Paul, AAA Northeast's Car Doctor, answers a question from a reader curious about using Marvel Mystery Oil. AP Photo/David Zalubowski ...

Marvel Mystery Oil, or MMO, — to the uninitiated, it may sound like a magical substance concocted from secret ingredients, and in some ways, that's exactly what it is. However, others may see it as ...

Before we get into the secret ingredients behind Marvel Mystery Oil, it's probably a good idea to first explain that the stuff is — because it sounds like something Spider-Man would use to refill his ...