Hi,
I have a 1986 944na and have been having some problems that I
initially thought were caused by the engine mounts.  However, I
switched out the engine mounts this past weekend (the old ones were
awful) and to my surprise the problem still remained.  The car
vibrates much less, and shifts more smoothly than before.  The issue I
am having is when I am actual driving (not at idle).  When I let off
the gas at virtually any RPM (except very low ones) there is a strong
shudder.  It happens in every gear, and can get quite violent if the
throttle is released suddenly.  If I disengage the clutch as I let off
the throttle, it either does not occur or barely present.  I suspect
this may be due to the rubber plate being deteriorated on the clutch,
but I am not certain.  The clutch feels good, there isn't a lot of
play and I do not have any slippage.  The idle is good, and I do not
tend to have any of the shudder problems associated with that.  I
guess I am trying to find out if there is anything else I can try
before I attempt a clutch replacement (or pay for one).  Not sure if I
am up to that project.  Anyone else have a similar issue with their
car?  Any suggestions/recommendations are appreciated!  Thanks!