I dont want to start another thread, since we are talking about tachometers, i should hijack this one

:
I got a 1987 300D Turbo Diesel, and when I 1st crank the car, the needle for RPM twitches/jumps little bit and after I start up the car, it stays down (like its dead).
You guys mention about the rpm thing is in the transmission, is it in my car or no? what about the amplifier? do i have it or no?
thanks for help guys!