Related Clues:

• The fill in 'fill 'er up!'
• Laughing matter?
• Hoot and a half
• Lorry fuel
• Flivver fuel
• Methane, for one
• Ethane or methane
• Methane, e.g.
• Pump stuff
• Electric alternative
• Nitrogen, for one
• Bug juice?
• Word that can precede the last word of the four longest puzzle answers
• Truck engine
• Bunsen burner fuel