I have a 95 Sentra GLE with a problem that doesnt happen all the time. The problem is sometimes the car runs at higher rpm's than other times. Example..1st day 60 mph @ 2200 rpm....next day 60 mph @ 3100 rpms. It did this to me a couple of months ago and stopped. It just started again yesterday. I can tell when it is going to happen because when I come to a stop the rpms will drop below 500. I thought maybe the overdrive switch, but when I turned it off the car ran at a much higher rpm. It is almost like the car has an extra gear. Could the overdrive be going out it self or could it be an electrical problem? Plus it only seems to do when it is hot outside. It did not do this all winter.......I appricate any and all help.