the revs go up and down but generally it runs at around 500?

hi guys hope you can help
my 95 320i e36...has very rough idling on startup and does not get any better when warmed up....it sounds like its running on 5cylinders....had this problem a while ago ...but it seemed to reset itself and not do it again...this time its there all the time...could it be the icv?
the revs go up and down but generally it runs at around 500 which shakes the car..seems to not be so good on the road performance wise either...any help would be great...thanks so much

__________________
This post was auto-generated based upon a question asked on our tech article page here:

[Nick at Pelican Parts]

Try unplugging each injector one at a time and make sure the rpm drop equally for each unplugged injector. You may also have a vacuum leak that can cause the idle to surge. Try spraying carb cleaner around the intake and when the rpm flares up when you spray in a certain area that is the source of you leak.

- Nick