Hi guys, i'm new to this forum and posting for the first time.  I have in my possesion an e36 318is coupe (m44 engine) year 99.  When my car sits at idle it seems to vibrate alot and miss-fire, i have taken the vehicle to various mecanics and main dealers but have had no luck, as no-one can seem to pin-point the problem.  Every single mechanic i have went to has stuck the car to so-called specialist diagnosit equipment and yet found no problems.  I most definately know that the miss-fire and vibration charectiristic of the car isn't normal, as at times I have sat in the car and felt NOT A SINGLE VIBRATION.  It has been as if the car was OFF.  Any advice would greatly be appreciated.