I notice vibration when im in 1st and reverse gear in my nsx under 2k rpm. Sometimes it'll shake/vibrate more or less depending on how you balance the clutch and the throttle. I noticed this when i bought my car about a week ago. I figured it was the clutch since it was going out. However, after replacing the clutch less than a week ago i still feel vibration when i balance the clutch and throttle. It shakes and vibrates more when im going up hills and drive ways from a stand still. Any ideas or help would be greatly appreciated! =)