sometime and only sometime the engine doesnt quite idle right and seems to run smoothly till about 1800 rpm range. but after about 1900 range it goes away and idles smoothand is more pernouced when it does do it if the AC is on, ive only owned this les than 2 months its got 48k and still has the factory powertrain warrantyand im gonna take it and have it looked at but i need to know if this is a 3v 4.6 thing or possibley something diferent.