history, 97 lesabre, new UIM, map code, replaced it, now have code for oxy sensor slow response. anybody? can clean it? or just replace, no money right now,lol.

Did the UIM leak coolant into the manifold? If the O2 was exposed to coolant, save some money & get a replacement. There is no way to "clean" an 02!

the funny thing is that i have put 4000 miles on it and just replaced the map sensor and then same day the o2 sensor showed up for first time

The MAP & 02 are both exposed to coolant ingestion from a UIM failure. The 02 will be more forgiving when it comes to faults (SES/CEL,s) and basically non-functional before the fault will appear. Coolant can damage the catalytic converter as well. You did not mention if you had coolant loss, but from the symptoms mentioned, I assume you did.

UPDATE...after driving about 50 miles or so the code cleared itself, prolly will have to replace it soon, but at least i know the map sensor was fixed