91 Honda Accord EX

my car idles rough. The rpms will go down to 500 then back up to 900 then settle at 700, when I let off the gas. Any help would be greatly appreciated.

Thanks

 

I had the same problem till my mechanic took a plug off a vacume line on the intake mani. If you look at your intake mani you should have like 3-4 (cant remember exactly) vacume lines coming off and the one at the very back will have a plug on it. Take it off and see if you still have the problem.

 

what do yo do with it when its off?? plug it?