I have a 98 4.2 w/ a 5 speed w/ 74,000 miles on it and my check engine light came on so i went down to auto zone to get it scanned and an Oxygen sensor code came up and it told me that the sensor that was tripping the code was Bank 2 Sensor 2 which im assuming is the one after the cat on the passenger side. Am i right? Also is this normal for an o2 sensor to malfunction so early? I just put a Gibson Super Truck exhaust on it would that make any difference? Is there any more investigating i should do before i put a new o2 sensor in it? I was thinking of just getting a Bosch sensor. Any help would be great.

Thx Matt

 

Bank 2 is the driver's side. Sensor 2 is the one after the cat.
It's not unusual for an O2 to fail with that few miles on it. Not real common but it does happen.
The sensors behind the cats arent actually used as O2 sensors but are for monitoring the cat function. If the cats arent working properly the sensors will pick that up.
When you installed the new exhaust on it did you do anything to the cats? If not then the new system shouldnt cause any problems.
I'd be inclined to get a genuine Ford sensor as some of the aftermarket ones I've seen weren't very good....connectors had to be spliced on etc.

 

racerguy knows better than me but sometimes the o2 sensor kicks off due to a problem that is upstream i.e. on the engine side of the sensor. this means the O2 sensor can seem like the problem when in fact the O2 is fine and something else is wrong.

 

Yup that's right
But usually a problem upstream would show up more on the upstream O2's.
The only thing between the upstream and downstream sensors here is the cat.