(2001 v6 manual stock just a cold air intake)Recently I've had a problem with my idle. When it's stopped its fine and sits around 850 or so. In the past couple weeks it's been acting up really bad. When drive and In-between shifts the Rpms will jump to about 3500 Rpms and stay there and not drop unless I throw it into a higher gear to make them drop or come to a complete stop. I thought it could've been electrical so I replaced my battery and alternator then it continued to do it so I seafoamed my car and did throttle body cleaner, it continued so I took off my cruise control cable and we'll still did it. I ran it for codes again and got nothing so I'm dumbstruck and do not know what else to do please help!! I'm tired of dumping money into this car