2002 Chrysler Concorde overreving

Are you getting any warning lights on the dash? Specifically the "TRAC" or "Check Engine"?

Your issue is a computer/sensor related problem. One/more of your sensors (probably a crankshaft position sensor) is acting up.

A bad CKP sensor will allow your engine to still run (Though it may cause the motor to stumble/stall or a hard start). But it will feed your computer false information.

I recently had a complete melt down of my CKP circuit and wiring. It sent my tack needle all over the place. And while in cruise control mode, it caused my engine to race up and down as though it was hunting for the correct speed.

This makes me suspect you have a similar problem.

What you should do is have your computer scanned for codes. If there are none, find an experienced technician who knows how to read a scanners data during a drive test. This will pinpoint the problem as it occurs.

Good luck.