I tried to check the cat converter last night. I have been told that if they break internally, they will sound like tin with gravel in it if you tap them, and they can even glow red where the blockage is. I have found no such symptoms. The exhaust seems to flow well enough too. The car still does miss, but only under load, and only when warm. I still think its fuel delivery (filter or something wrong with the pump) but that is just a guess.

I checked two plugs as I had little time before it got dark ( plugs were malt brown/tan and healthy looking) and I could find no flaw or significant wear on the distributor. If a vacuum leak were to occur with the vacuum advance on the distributor would that cause such an issue? It almost seems as if the ignition cuts to one cylinder when under load, any clue what would cause that to suddenly start happening?

I love this shotgun approach to problem solving.

At any rate, the best price I have seen for a new non-oem cat is US$599, but I can get a used, good condition one for CDN$400. Here in Canada there is no law against reusing such parts.