RPM gauge shuttering

[betterxthanxnew]

Okay so here is the situation, I've been dealing with it for quite some time, and we just can't seem to fix the problem. We've replaced spark plugs and the fuel filter. Just not sure where to go from here. I have a 2005 Chevroler Cavalier, stripped down model. The car drives fine, but when I am in park with the car turned on, or when I am at a stop light (or anywhere completely stopped but still in drive) my rpm gauge kind of surges. It goes up and down, and the whole car feels it. As soon as I start driving it stops. This only happens when the car is at a complete stop, either in park or drive. It's been this way for over a year, and the problem has never gotten any better or worse. But I really want to fix it. Does anyone have any ideas as to what this could be, or what I could check?
Thanks!

[viggy58]

start looking for vacuum leaks. maybe do a smoke test.

any codes?

[Scrapper]

Originally Posted by viggy58

start looking for vacuum leaks. maybe do a smoke test.

any codes?

i would also look for vacuum leaks and have look and made sure all your plug ends on wireing? because it could be iac, and if this is a multiport fuel injecton if so look in at the butter fly in throttle body to see if it's needs a clean? you could unplug 0-2 sensor and see if it makes any diffirent?