TECHRON (made by Chevron) is THE BEST fuel system clean-up /keep clean additive for GASOLINE engines. It is THE ONLY detergent additive used in the special gasoline that is used for all EPA emissions and mileage certification testing. Several major brand gasolines are now using it and similar very effective detergent/dispersant additive packages in their gasolines and advertising 'clean-up' or 'drive clean' or similar capability. That performance HAS been documented and proven by independent testing laboratories before the advertising goes on the pump.

The 'white crud' found in the bottom of the gasoline tanks 'may' have been either a water/gasoline emulsion (most likely) or a caustic/water emulsion-possible but unlikely. I strongly recomend you contact the station owner and operator AND WALMART and report your observations. If it was really contamination from their fuel--they ARE responsible for the repairs. This kind of misfiring can destroy the catalytic mufflers quickly. Selling a gasoline that does not meet the federal requirements is a big NO-NO and can subject the station owner/operator to very large fines because it can destroy the cat mufflers.