Coil packs
I had the same problem about a month ago. One or more of your coil packs have gone. This has two effects: Firstly, the engine is not running on all cylinders, and therefore runs like a bag of nail (and high fuel). Secondly, the unspent fuel contaminates the combustion gas sensor leading to the light on your dash. Once the offendind coil pack is changed it will take ~50 miles for the light to go off.