Honda engine question

I have a 1999 Honda Accord EX Coupe with 190K miles. I got the transmission rebuilt last summer, in August 05. Recently, the car has had trouble starting. I usually have to try a couple times and wait a couple minutes in between starting. It usually starts after a couple of attempts. Today, the car jerked in lower gears and even cut off. I was driving at around 30 mph. The key light came on, then all of the lights and teh car stopped accelerating when I stepped on the gas. I came ot a stop and turned the car off. I tried twice and the car finally restarted, jerking in lower gears. My check engine light is on. My dad took it to Auto Zone and said the code indicates the car needs a new O2 Sensor. He bought the part and I was going to take it to a shop today to put in. Do you think this is the problem?