Lexus Troubleshooting Questions? Ask a Lexus Expert
Is the yellow check in July currently on? Do you have a code reader to check for malfunction codes that may be set in the computer? You mentioned about having a scanner showing a problem but I need the specific code numbers.
To answer your question specifically no the oxygen sensor will not directly cause a huge loss of acceleration. However you can lose about 10% of the performance if the oxygen sensor shorts out or quits producing a signal. By default there are settings in the computer to allow the vehicle to accelerate usually unnoticed if an oxygen sensor fails.