I'm not sure if this has already been posted before, but when I am sitting at a stop and the car is idling, my tach needle starts twitching. It usually idles just under 1k, and will go from that to near 0, back and forth. It's not really consistent, it does it whenever I drive but there is no rhythm to the times it does it or anything. I've also noticed it sometimes cruising at highway speeds. The engine itself is not changing revs at all, so I'm hoping it's some sort of sensor. Anyone know what it is?