well guys, i replaced the IAC. but the RPMs are still acting funny. it mostly does it after down shifting when i press in the clutch. the RPMs drop to like 4 or 5 hundred, then shoot up to 11 or 12 hundred. then go back to idle at 800 (thats what i set it at with my tuner). sometimes, the car even dies (i look really cool when that happens). i think i could have a slight exhaust leak. when driving by curbs and walls i can hear a "pppsssssssssss" sound. i have tried many times, readjusting my X, to fix the leak. no luck on that. could this slight exhaust leak have something to do with my RPMs fluttering. or could it be some other problem?? thanks for the help guys.