1989 lesabre intermitant SES light

just got my lesabre back on the road yesterday, car runs great but it seems when i drive on slight inclines the Service engine soon light will illuminate for about 10-30 seconds and go out. so this morning i checked the coded via jumpering pins A/B and pulled a code 13. which tells me it is the oxygen sensor. the vehicle has 29,000 origional miles on it, and is an 89'. does this sound correct. The vehicle runs great at all times, does not hesitate at all, and does not spit sputter or stall at all, even when stopped. Does this sound like an oygen sensor? i should add that the exaust does smell a tad bit bothering to the nose, cant exactly explain it but its not a gasoline type of smell, and i should also add that the entire exaust pipes, muffler and CAT were replaced 1000 miles ago. and its possible this smell is coming from the CAT but i dont know, anyone have ideas?

Bump, anyone know where the oxygewn sensor is located on this vehicle, i am looking on top of the muffler just to the rear of the engine where the muffler bolts to the manifold, i have a small type of connection with a single wire connecting to it, is this it? if not where is it and can you describe it.

I assume you are refering to the cat instead of the muffler. If so, I think you have found it! It has one wire and favors a spark plug. lol

yes, with a small metal type cap covering it. I assume i use a spark plug wrench 13/16 to remove the o2 sensor?

anyone?

Yes, Autozone is supposed to have free loaner socket tool to get it out, but I just used a big crescent wrench.