you know i had a similar issue with my 98 v70. All it took was a new mass air flow sensor (commonly called a Mass Air Meter). About 50-300 at a junkyard, depending on the state of the vehicle at salvage. Try disconnecting the mass air electrical plug(the first thing you see after the air filter, if you go from right to left. I wouldn't reccomend driving like this, but it can be done. just check to see if it idles correctly after you do that. If it does, the problem is isolated, but ask a mechanic first.