I have a 2002 Nissan Maxima. The other day, at a stop light I hit the gas and there car didn't go and the engine didnt rev. After it was turned off and back on it fired up to just to do the same again at a different light. Then it started to act like it had a dead battery. Since then the alternator was changed (battery was 2 months old) it did the same thing again 2 days later (drove for a day). That is, it was started after sitting overnight, drove a quarter mile, was shut off for 3 hours, started up and then the gas pedal wouldn't rev the engine when it was put in gear. Now its sitting so it doesnt die on the road. Some one said the O2 sensor could go bad and drain the battery? Any ideas?