I am certainly not an expert when it comes to vehicles, but my husband is a mechanic and has been for 15+ years. From what he has explained to me, you COULD put in a lesser grade fuel, but your vehicle will burn gas a lot faster and not perform as well. NEVER put deisel (sp?) or ethanol fuel in a vehicle not specifically designed for flex fuel options. That spells an engine lock up and a new engine! Good luck, hope that helps!