I got three issues that I would say are due to buggered o2 sensors:

1. I get a 15 mpg on the highway

2. When driving for about 2 minutes, the engine sometimes drops power completely, and then going on as nothing has happened within 5 seconds.

3. In about 1 in 5 starts I need to help the engine with starting, by pressing the gas pedal.

Can these problems due to a faulty o2 sensor?

 

Anything is possible. Engine light on? Scanned it for codes?
Any tune up history? You could try unplugging it for a while and see if your symptoms change....

 

Engine light is on, but no o2 code.
Just bought the car and no history. But my guess is that it hasn't been looked after for quite a while.

I unplugged the upstream sensor and gave it a quick drive. No noticeable difference, but also no problems.