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The Oxygen sensor will not cause this problem. This is normally a problem in the throttle control circuits. Either a fault in the pedal sensor or in the throttle position sensor in the throttle body. This will usually set other trouble codes.
You definitely should start with an in depth diagnosis using the dealers scan tool. This usually runs $100-120.
If the problem ends up being in the throttle body, the replacement cost would be around $450.
If any wiring needs to be repaired/replaced the cost would usually be another $100.
Until you have the diagnostic done, you will not know for sure if the throttle body or the accelerator pedal position sensor or the wiring is the problem.