I have a 1995 civic ex and i am having promblems with the idling it will sit there and go from 1000 rpm to 2500 on its on just back and forth and i was wondering what it could be?

 

Throttle cable too tight.

Stuck IACV. Clean it.

Stuck Fast Idle Valve. Take the air hose from the filter box off of the throttle body. Start the engine. Hold your finger over the port on the bottom of the throttle body outside the throttle plate. If it's sucking air there when the engine is warmed up, the FICV is bad.

Major vacuum leak. Check that the bolts holding the throttle body to the manifold and those holding the manifold to the engine are tight, and if you just acquired the car, that gaskets are in place.

 

If those ideas don't happen to pan out, then try bleeding the cooling system of possible trapped air, which also can cause a hunting idle.