tach twitching

Lately my tachometer has been twitching when I get around 2500 RPM. It just started a month or two ago and has become more frequent when i reach 2500 lately.

And just yesterday when I noticed for the first time that it twitched when I was idling at the light. It was at 800 and dropped to 500 back and forth. It hasn't happened again but I'm afraid that it'll become like the other twitch.

It doesn't do that at any other RPM and I was wonder what the cause of this would be.

Mine did that when my alternator was ready to go out. Bud it did it at other rpms too.

Open your hood when the car is idling, if it sounds like there is a small rock kicking around in your distributor... you might need another one