Here's the deal. The car doesn't like to run anymore, symptoms.....
Jumpy Tach
Misfires like a big dog
Extremely Rich
Melted the cat

Possible causes........

Faulty injector(s)
Bad distributor
Bad ECU

Tried...........
Different distributor
Different ECU

Going to swap out the cat and go from there.

What I do know.....
Plugs are not fouled
Car ran great for the longest time
A/F gauge read rich for about 2 days.

Any other ideas???