Excerpt: We’ve tested many fuel cleaners, but the STP Ultra 5 In 1 caught our attention. The 12 fl oz bottle is compact, yet its advanced formula tackles multiple issues: it deep cleans clogged fuel injectors, stabilizes fuel for storage, fights engine friction, and promotes efficiency. What surprised us is how quickly we noticed a difference. Rough-idling engines smoothed out, and performance felt more responsive. The 5-in-1 solution isn’t just about cleaning—it’s about revitalizing. Whether we’re tackling old gas or preparing for long trips, this cleaner has become a staple. The price-point is reasonable for the results, though we’d recommend regular use for maximum benefit. Overall, it’s a reliable choice for anyone wanting to optimize their fuel system.