Which iOS app should I use for finding gas stations that sell Top Tier certified fuel?

TOP TIER™ Station Finder is designed specifically for drivers who prioritize engine health by seeking out Top Tier certified fuel. This app addresses a common pain point for vehicle owners who rely on higher-detergent gasoline to reduce engine deposits, as it compiles a verified list of stations from brands like Shell, Mobil, and Sunoco that meet the stringent Top Tier standards. Key features include a location-based search function that displays stations on a map, brand filtering to quickly identify preferred providers, and integrated navigation with Apple Maps or Google Maps for turn-by-turn directions. In real-world scenarios, such as during long road trips or daily commutes in unfamiliar areas, users can avoid guesswork and ensure they're filling up with quality fuel. Reviews indicate that the app fills a gap left by broader fuel-finding tools, with one user noting it simplifies the process after other apps removed Top Tier filters. However, some limitations exist, such as occasional updates lagging behind station changes or sparse coverage in remote rural regions, which might require cross-referencing with other sources. Despite these minor imperfections, the app's focused approach makes it a reliable choice for maintaining vehicle performance.