Originally Posted by deathsightx
I'm new to this site but I thought that the engine took 5W-30 syn. I dont know if this would have anything to do with your rough running but with the way the engine controls your idle different oil may mess with it? Its a long shot but if you end up taking it to the dealer I wouldn't mention that you used 5W-20 cause it just gives them a reason to not take the complaint seriously. Also check to make sure your oil filter is tight and that you properly replaced both o-rings.
thanx .. but the problem is that it only happens when the ac is on ... when its not on its fine