Rep Power: 349

i finally got my car back from the shop the other day (long story, its been gone 4 months) and they lost one of the o2 sensors. so they ordered a new one but for the past couple of days ive been driving around with one missing and my a/f gauge has been telling me my car is running rich the entire time its on. its also making my exhaust sound like ***. is this bad for the engine? or the car in general? just wondering.

 
Rep Power: 453

Just dont drive untill they get it.