Symptoms:  car idles slow and misfires except when accelerating.
Doesn't start sometimes after shutting down for a couple of minutes and
sometimes stalls at traffic lights.  It always starts after a minute or
two.  Sometimes there is a slight "grating" noise.
I replaced the distributor, cap, rotor, ignitor, ignition coil, plugs,
wires and fuel filter (and boy, was that filter hard to get out).
When setting the timing, the timing light misses, i.e., it doesn't fire
every time it should.  That could be because it's old, but I don't
think so.  It was the reason I replaced some of the ignition parts.
The ignition coil was out of spec, actually on what I consider the
"good" side but not according to the shop manual.
I have pulled out the "main" relay (from under the dash, beside the
steering column) and the soldering looks perfect.
The car has 105,000 miles.  The timing belt has not been replaced.
I have run two fuel injector treatments through the car.
The "check engine" light is not illuminated.
If they weren't so expensive, I'd replace the engine relays (especially
in the fuel system).
Got any good ideas?  
Jojo