Will it hurt your engine if you mix Costco gas with shell gas?

Mixing Costco gas with Shell gas generally won't hurt your engine, as both fuels typically meet the same industry standards. However, there could be slight differences in additives and octane ratings, which might affect performance or efficiency. If done occasionally, it should not cause any significant issues, but regularly using the same brand can help ensure optimal performance. Always check your vehicle's manual for any specific recommendations regarding fuel type.