I have a 2005 Impreza 2.0gx , it has been running very rough over the past few weeks , idles rough , and when driving in gear it try's to drive by itself and when you put it out of gear it over revs past 1500 Rpm and stays there , when idling it revs up and down , won't settle unless car isn't moving for a few minutes , I have replaced the idle control valve , but it's still doing the same thing ,can anyone help me please

 

Start with the basics before replacing random parts.

Check hoses for splits or connections, clean the maf (brake cleaner), get a code reader and check for codes