[T77911S]

very good explanation of your problem with all the right info. you seem to have a good handle on CIS already so that is good.

as paul has suggested, air leaks are always a good place to start. the injector sleeves are often overlooked.

timing? im not so sure about, fuel mixture, definately can be a cause of what is going on, which is tied into air leaks. since it sounds like you have already played with the mixture, i would go ahead and try it a little richer. try richening it up, warm, to the point it wants to either surge or when you blip the throttle, the rpm's dip when they come back down. then, lean it out to where it just stops doing both.

i did not see where you mentioned brand of plugs, but copper tops as paul said are the best.

is your vacuum circuit still connected to the WUR? and is the thermo time valve (TTV) still installed?

just curious. how is the ignition system? bosch CD?

new distributor and fuel distributor?