My 2005 3.8 Town and Country has had a few episodes where the car all of the sudden starts to loose power and feel like its going to stall, otherwise it runs normal. Malfunction light came on and I got the code P0132 code from the key dance...Autozone also scanned and verified Upstream Oxygen Sensor. Is replacing this a difficult job? Do I attack this from under the hood or underneath. Any help would be appreciated.