The data indicates that nearly all 'Mercedes-Benz CLK (2002-09) 240 2DR Coupe 2.6 Avantgarde Auto' models are equipped with a 2.6-litre petrol engine, accounting for 99.5% of the vehicles. Additionally, the primary fuel used is petrol, also at 99.5%. A small proportion, 0.5%, runs on gas bi-fuel systems, highlighting that the vast majority of these vehicles are petrol-powered with straightforward fuel configurations.