Not-running 90q (was poorly-running)

[DePenning, Charles [EPM/MTN]]

I'm still scratching my head with my '89 90q that flatly refuses to run
right.  Very lumpy idle, no power at all, sounds like it's missing on a few
cylinders.  Happened suddenly at highway speed.  I've been working with the
assistance of folks on this list to cure the problem, working mainly on the
CIS side of things.  I've checked and double-checked about everything I can,
and all components look to be right in spec.  Exhaust is open- no clogged
cat.  Last night I just let the car run until it was well warmed-up, and the
missing behavior got worse and worse, until it sounded like it was running
on 2 cylinders, barely staying running, with some very strange 'clanking'
sounds coming from the engine- sounded like mechanical interference, but
might have been pre-detonation or knocking, which sounds similar.  Then it
died, and would not re-start.  I had a thought that maybe the gas was bad
enough after sitting for three months that maybe it was causing the problem-
not likely, but I've tried about everything else.  So I drained the gas from
the tank (using the fuel pump through the fuel return line in the engine
compartment) and put 5 gallons of fresh gas in the tank.  Still just
wouldn't start.  I waited until this morning, engine cool.  No start.
Before, I could at least get it to start and run lumpily.  Now nothing.  I
pulled all five plugs and checked spark at each- good.  Compression still
good.  Each cylinder smelled of gas and the plugs were slightly wet and I
could see a little gas on top of the pistons.  I am at a loss to find what
is steadily getting so non-functional that with fuel and spark both present,
I can't get the thing to even fire a little.  Any help would greatly be
appreciated!  

TIA,

Charley DePenning
'89 90q
'84 4kq
'83 5kT