i'm and electrician, not a mechanic, so i don't know what i'm
talking about, with these cars, but it hasn't stopped me yet..
that said... if it were me, and i had done all those things to
the fuel system, and the car still acted up, i would start
looking at an electrical problem.. ?.. have you replaced the
cap and rotor? inspected for minute cracks in the cap, and or
tracking? .. changed the CONDENSOR? replaced the plug wires? ..
how old are THEY? ...
just some thoughts to add to your confusion :-)