1993 s10 blazer 02 sensor trouble

Please, help....

I have a 1993 s10 blazer with the 4.3 vortec engine. I bought the truck near two years ago and everything seemed to run fine until about a few months ago.

It started to rough idle and we put a scanner on it. It shows code 13 (oxygen sensor), but when we go to change it, there's no place for it. The truck has been parked now for months and would really love to drive it again...any help would be appreciated.

Would also like to know if we may have ruined the engine by running it the whole time with no 02 sensor?

Thanks.....

The sensor is located in front of the cat. convertor, towards the top of the exhaust pipe. Most likley the engine is fine, might be carboned up if it was running rich for awhile now. You can decarbonize the engine and you should be good to go. Also if its running rich, its also a good idea to change the oil, to much gas can get into the oil and break it down, causing more wear.