jon blaze

Alright I hope someone has an idea what my problem migh be here, i drive a 93 civic hatch with the stock d16z6 engine. The other day i noticed that after only a few minutes of driving the engine seemed to be idling alot higher than normal (roughly about 2000 rpm). Then a few minutes after that i noticed that whenever had the clutch in and my foot off the gas my rpm would drop way below 1000 then rev itself back up to 2000 and then drop back down again. It does this over and over as if i was actually revving the engine myself. It seems weird because if i'm driving, accelerating etc theres no issue everything runs fine, but as soon as i come to a stop or depress the clutch it does this stupid thing. Anyone got any ideas what my problem could be here??