I have tried to find a good image in archive but have been unsuccessful. Could anyone tell me how long the white portion should be? It seem sto go in with a little pressure and pops out quickly but it is very short (1/4" or so)
Thanks!

 

sounds about right

 

I recently replaced mine. On a new Dash Pot the white plastic piston protudes over 1/2".
The old one would only extend out to 1/4".

http://www.rx7city.com/Manuals/93%20..._EMISSIONS.pdf

Page F-134 for proper adjustment.

 

The dash pot deffinately sticks out more than 1/4" when new. It should have resistance going in and return rapidly. This may be why the idle drops slowly on a properly working dash pot after blipping the throttle. I also belive it's to prevent the butterflies from slamming shut when jumpping off the accelerator. Any insight to the logic of having this piece on the TB as many of the ones I have polished were in the 1/4' range and provided poor dampening/

 

1/4" is not what it should be, but it may be enough. As I recall, the correct adjustment is to have the dashpot just touching the throttle return at about 1700 rpm (it's been a while since I looked that one up). Look it up in the FSM to be sure. If you can still get it to adjust properly, you won't have to replace it.