What is causing EPC light to come on? Can I fix this myself?

What is your question?

Last week the check engine light came on for about 3 days and turned off. I contacted the dealer and they said probably gas cap. Then now the EPC light is coming on and the car starts and drives, but it sort of feels off. Is this something I can fix, such as a fuse, or is this something for the dealer to fix? Is it anything major? The car is at 194k if that helps. Your thoughts are greatly appreciated!!