Engine idles rough,no power and high fuel consumption.

Sounds like a misfire but it’s hard to say without knowing more information about the circumstances and environmental factors when this began occurring. Do you have any other info you could provide? And just a heads up….Amazon and eBay both have very inexpensive OBD2 scanners for sale (<$30) that will allow you to connect to your car’s computer so you can read the trouble codes and hopefully correct whatever is causing it to do that