1996 buick roadmaster runs rough when idling and skipping

[leebooth15]

I have a 1996 Buick Roadmaster 350 LT1 5.7, I am having some issues with the vehicle idling rough and seems to be missing. When I turn on the AC the car runs a little better and sometimes after shutting the AC OFF THE CAR SHUTS OFF.I went to AutoZone and had my car put on the computer and I got a EGR code P0400, Mass Air Flow code P0100, and a Catalyst code P0430. I replace the EGR, and mass air flow sensor, and my car is still doing the same thing. I was also told I may have a leaky water pump. I just recently installed new AC DELCO plugs and wires and a new air filter. Any ideas on what to try next or what could be my problem?
NEW PARTS INSTALLED:
PLUGS
WIRES
AIR FILTER
EGR VALVE
MASS AIR FLOW SENSOR

See a video of my car running

[SMWS6TA]

How many miles with the Opti-spark?

[0rion]

if you have a leaky water pump that would lead me to believe it's the opti......the LT1 motors are notorious for the water pumps leaking onto the opti and killing it.

[pajeff02]

^^ This. But first double check that you have your plug wires plugged in correctly at the opti as crossed up wires will cause similar issues.

[leebooth15]

UPDATE!!!!!! After replacing the EGR and Mass Air Flow sensor I did not unplug the battery cable to reset the computer, so after doing that the check engine light went off for about 2 days and it came back on yesterday so I went to AutoZone and had it placed on the computer and the only code I got was the P04030 indicating that the Catalytic Converter is bad. I wonder is the code just a reference to a bigger problem or since it is the only code showing up ,is that my problem the actual CAT CONVERTER?Should I go ahead and replace it?

[pajeff02]

A lot of times, a bad cat code is likely the rear O2 sender acting up or its wiring. Any rattling in the exhaust or chunks blowing out the tailpipe? Is it now running like it should?