Check engine light and cruise control flashing

I have an 05 Subaru Forester with 76,000 which has been to the dealership 5 times in the past three weeks. They keep telling me that the 02 sensor is bad so now we are on the 4th one and still the check engine light is present. The cruise control light is also flashing and the car doesn’t sound so great when it’s warm. They are saying it’s just a bad sensor again and i’m thinkin they are beating around the bush. I’m thinking it could be the Catylitic converter or maybe a fuel pump, or even spark plugs. I just don’t know anymore but i’m tired of walking when they are out of rentals. Any ideas?