Under normal circumstances, most modern engine oil and gasoline brands work fine on their own to keep your engine running smoothly. But there may be cases where even the best of them could use a ...

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

If you thought diesel fuel additives were merely store-bought products at your favorite auto store, you'd better think again. Fuel suppliers, refineries, and manufacturers are the biggest market for ...