Need help
 

I recently changed the starter on 2001 eclipse GT to get it back in I pulled the sensor on the exhaust. Starts fine but after it warms up it stalls. Is this a sensor problem?

do you re-install it. That is the upsteam O2 sensor and if its not in the car wont run correctly

Yes I did and I think this is the downsteam sensor I did not take the upsteam one out

maybe there is a ground or something that you forgot to re-install or attach correctly. I must be something to do with your install if it didnt do this before. Have you tried checking the voltage at the battery when its running