2000 pontiac grand am se 2.4l high RPM / low speed gain / shifting issues / feels like it's going to turn off when on any shift exept Neutral? help...

The first thing I would do is take it to a shop and have them preform a transmission flush. That will get all the build up and gunk out of your system. Have your idle air control valve cleaned. A plugged valve will mess with your RPM's. If problem still persists after tranny flush and idle air control valve cleaning, replace your throttle position sensor.

The hi revving sounds like it could be a throttle position sensor, but the other symptoms suggests a possible vacuum leak. There are so many possibilities now with these computer controlled engines. May also be a mass air flow sensor. Find a good mechanic you can trust and let him help you make a diagnosis.

Umine does the same thing every so often . i stop turn off car restart serms to work. Has so far