Minor rev issues

[PhyscoDboy]

Alright, i've been slowly bringing an 89 LX-I back to life. FInally got it runnin last night. It runs like a champ but when I first start it(after t warms up) It will rev to about 2000 then drop to 900 then rev to 2000 then drop to 900... Over and over and over, If I drive it for a minute itll go away. I have a few ideas but i'd like to get an opinion or two from here, because I know this is a problem people get with these cars now and again.

[PhyscoDboy]

Oh hey i'll answer your question! Hope this isnt too late, your a dumbass! Quit asking stupid questions, noone cares!