Why would your 2004 Sunfire be over revving?

your sunfire is revving if the idle is set to high, or when adjusted. the idle is high also when the engine needs to warm up in cold weather. there is also the possibility that the engine temp sensor needs to be replaced, for it is not relaying proper heat temp. the light on your dash may show you engine temp, check this. if unable to do this yourself, you may need your cars manual.