I have been past due on my oil change for about 1.5K. I started up my car last weekend to to have dinner with my girl and i noticed that i was getting alittle bit of rough idling when parked. It does not seem much (like a vacuum leak or sumthing) just a little twitch of the needle once in a while. I would like to see what i can do to fix this so i can keep my Z in tip top shape. As mentioned before the idle does not bounce around much but will have alittle flectuations. I think the problem may be caused due to the past due oil change but not too sure. Experienced Z owners input appreciated. Thanks!!!!