quick oxygen censor question!
 

alright you remember my car threw code 61 which means:
Oxygen Sensor, Heated - Sensor 1 (Primary) high voltage, low voltage, or slow response

anyways, I am pretty sure i need to replace the primary oxygen sensor so i'm going to go ahead and do it...however, i just want to make sure that the PRIMARY O2 SENSOR mentioned above is indeed the one that comes BEFORE the catalytic converter? correct?


also, i reset the CEL and every now and then when i fire up my car, it will rev up, then down, up, down (ex. 800rpm, 1500rpm, 800, 1500 and so forth) and then it stops after i drive for a bit....what is that all about?!

PCV vavle is bad or you have a vaccum hose disconnected.

and yea thats the right o2 sensor.

PCV valve is bad that causes the jump in rpm or the bad o2 sensor?

pcv