I have a 1997 Saturn, and have noticed for the past couple of months that when the car is idling at a stoplight, the engine seems to rev or almost skip a little bit. The RPMs go from about 1000 down to 500 for a couple of seconds, and this will happen once every 10 seconds or so. Otherwise, it runs fine…but this is happening more and more frequently than it used to.
I had the transmission rebuilt over the summer and its still under warranty. Any ideas of what might be causing this?