20v stalling - out of town of course...

[Dan Sinclair]

Hi all,

My '90 Coupe Q has decided to run amuck on a weekend away from home -
perfect...

Quick question:  Should the 20v (non-turbo) stammer and/or stall if you pull
the dipstick or open the oil fill cap?  Mine doesn't seem to be phased at
all by either.  I'm thinking major vacuum leak (hence the stalling) but I
can't see a single hose or connection that's amiss.  My 10v used to respond
to the dipstick test - but is the 20v any different?

Symptoms for those with theories:  Engine spins down and overshoots idle,
studders, stalls.  Engine spins down very slowly.  With a blip of the
throttle, the engine RPM will take a couple seconds to spin down from 4000
to idle - not normal.  It usually just drops like a rock to 1500 and settles
to idle.  Idle is also rough and surges (hunts) on occasion.  My spark plugs
(brand new) were completely carboned up after my 4 hour drive to town.
Changed the plugs but no difference in running/symptoms.

Any input welcomed - thank!

-Dan
1990 CQ