'90 80q randomly stumbles and dies: bad ignition coil?

[Darringer, Chris]

Hello listers,

I have a pretty annoying problem right now that has left me stranded three
times.  Here is what I know:

(1) Car will run fine most of the time.  Every once in a while, a few
minutes after driving, usually during acceleration, the engine stumbles and
dies.  Restarting the car is hard, but after a dozen or so tries, the car
stumbles back to life, and is eventually fine for the rest of the day.

(2) When the car was stumbling the last time, I heard a "clicking" sound
near the ignition coil.  The clicking sound was the same frequency as the
car's ignition timing.  When the clicking disappeared, the car was fine.
Sounded like high voltage shorting to me.  I twisted the ignition wire, but
that did not have a significant impact on the clicking.  I also moved a few
nearby wires away from the ignition coil - this also did not change the
stumbling significantly.

(3) On occasions where the car died, it was either raining or there was
significant humidity in the air (maybe a coincidence).

(4) Before car died, it took an extra second or two to get the car initially
started.

(4) Ignition wires are about 1 year old.

(5) Distributor cap and rotor are new.

(6) Fuel pressure and timing have been measured when car is running
correctly, and are within spec, although fuel pump is on its last legs.

So, are these symptoms of a bad ignition coil?

If not, what are other possible culprits?

Are there any gotchas to replacing the ignition coil?  How much time does
this typically take?

As always, thanks for your time,

Chris
'90 80q-q-qu-quatt-t-t-t <cough, sputter, gasp> r-rr-ooo!