99 cavy...low rpms

i have a 99 cav. RS 2.2L, w/about 65000 mi. its running a little hard, and is dropping rpms at idle...it idles at about 1000rpms, and is dropping to btwn 600-500 rpms...feels like it wants to stall...does the same thing when i'm driving, but i cant gauge the rpm drop...i took it in to get hooked up to the computer, they said there was nothing wrong w/it, cleaned carbon off it, and added fuel injector cleaner...i'm gonna change the fuel filter, and spark plugs/wires...other than that...i'm at a loss...any help'd be appreciated

I think if you get new spark plugs and clean the fuel injection, you should be fine.