I own a 1992 Bmw 325is. Lately when i have been driving, i have noticed a short quick nasty vibration underneath car when i punch the gas. I notice it when i am about 3000 rpms in 1st gear and i punch it. and when i shift into second i notice it vibrating around 3000 rpms when i get on it. it only lasts about a second but the sound sounds really bad. It sounds like it is coming from the drivetrain or something just underneath the armrest in the middle of the car. the stick shift does not shake itself but it might be the actual transmission. The car drives fine and after 1st and second the gears go by very nicely and sound great. If anybody can help me that would be great.