I am having late shifting in a 1985 300Dt (CA; 722.416). So there's a modulator [corrected: amplifier] and a vac control valve on the IP.

I have good vac to vac control valve (the valve on the IP). I have good vac to the amplifier, and the amp sucks on the tranny line at about 17" at idle.

But when I pull on throttle, pressure only drops to say 14", then jerks around briefly, and even at full throttle I cant get it to drop much below 8-9" (presuming that close to 0 is where I need to be at full throttle).

The lack of pressure drop and the jerky pressure needle lead me to believe that my pressure curve to tranny is messed. Now I am trying to figure out whether to purchase a vac control valve or a modulator [correction: amplifier], or maybe neither if I can adjust. AND, I cant figure out if the line coming off the bottom of the vac control valve goes anywhere; cuz it's just hanging there on mine.

THANKS. NEED HELP!