contour w/codes p1131 & p171

my 96 contour w/84k miles check engine light is on and the car stalls frequently whenever at a stop. @ autozone, these are the codes they gave me:p1131 and p171. searchin the net, it sounds like a fairly common o2 sensor repair. i would like to do the repair myself, but don't know where they are located around the car... also, what is it exactly i purchase? any help would be greatly appreciated....
also, would this cause my temp gauge not to reach the normal range??? not sure if these problems are related to each other... it pumps out good heat and all my fluids are full... anyways thanx again

Theses 2 codes are saying that the computer is correcting rich for a overly lean condition. The O2 is most likely not bad. The engine is running lean. this could be vacuum leak, fuel system malfunction, egr malfunction, engine oil level to high.
The best way to be sure is to check O2 sensor outpput. You didn't say which engine you had but the O2 that are use here will be in the exhaust manifold.

i have the v6 engine... could the 2 problems(low operating temperature and the frequent stalling) are related then???? hmmm, i was hoping to get away w/a simple sensor replacement.... so i take it this is a job for a repair shop.. arg!!

is there anything i can do at home to troubleshoot further???