A fault with any of those can cause a misfire, but those are not the only things that can cause a misfire. In your first post you mentioned sparks around the distributor cap: that could indicate a probem with the the cap, rotor, wires, or spark plugs. Replacing the cap & rotor would be a good place to start. These things are real fussy when it comes to secondary ignition parts, so make sure you use AC Delco only. Put a dab of silicone dielectric grease on each terminal, inside and out, of the cap.

 

Could also very well be a problem with the fuel injection spider under the plenum. Thats the thing in the picture above that actually looks like a spider. These are notoriously problematic.