I am the proud owner of a Nissan. I recently changed my alternator but I am still experiencing problems. At startup the alternator is giving off a normal charge but when it warms up and idles for a while it begins to give a low charge when tested.I did the battery drain test and found the power windows giving off a drain. I removed the fuse and still have a problem. Sometimes when I drive the car it seems to be sluggish and hesitates.

Does anyone have any suggestions?