Slight motor rumbling

Got a BA Mk2 SR. Teenager when I bought it...with my own money so naturally I love it to bits. Since I bought it Ive taken it back to service 3 times, for the same problem. The car shakes when in idol. Use to stall but that problem was fixed after the 1st service. ECU apparently(had an update). But after the 2nd service the car still shakes. Took it in for a 3rd time and its much better...or am I just deluding myself. Been so long that Ive driven the car without problems that Ive forgoten what normal is. The car still viabrates alittle in idol. Am I being paranoid or is there something still wrong with my car? Can someone please tell me if there BA has even the slightest shake or vibration in idol.