1989 Accord SE-I Idle Problem

[twstice]

I have a 1989 Honda Accord SE-I 2.0 four cylinder fuel injected w/ auto transmission. it has 190k miles on it and runs fine until recently. I got in the car yesterday morning, start it, and it revs up to about 2,000 rpms(normal warm-up) but then it raises slowly up to 3,000 rpms and sits there. I finally put the car in gear and leave. It seems to be driving fine till i get a little ways down the road and let off the gas, it feels like the accelerator is stuck and its goin by itself, so i put the car in neutral and roll to a stop. It is idling ver erratic : from a normal idle, it revs way up 2,000 rpm and then stops and goes right back down to idle, then back up again, then down, etc. And it just keeps doing that. Any ideas on what would cause this? Thanks.