Mind of its own

Started the engine after work today (1.6MPI) and sat in the car for a few minutes so I could use the heater (Isnt it freezing out :( ) I lightly pressed the accelerator, and over a few minutes I noticed that If I Revved the engine to 2k, It dropped back down to idle then revved itself back to 2k, An exact copy of what I had done, this happened several times, Is it just a coincidence or is my car turnin into a Modern day Christine, by Stephen king. Do they all do this or will I have to be picked up with a shovel if I displease it?