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

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 ...

We may receive a commission on purchases made from links. Drivers trying to get the most performance out of their diesel trucks — and there are many things you can do — will sometimes resort to fuel ...

FARGO, N.D. - Yes, North Dakota State University has indeed tested the fuel additive CA-40. The tests - replicated six times in a laboratory - show no significant improvement, either in horsepower or ...