Misfire can be spark plug, plug wire, coil, injector, or low compression (sticky or burnt valve, cracked ring, etc.).

301, 420, 430, none of those have anything to do with the EGR.

I still think you NEED to get over to a muffler shop and check your cats (and the rest of your exhaust) for excessive back pressure.

 

Can I flip the cat?
Would bad cat cause the bucking n jerking? What about the po301 code? Check engine light is blinking occasionally.

 

Why are you fighting me? Go get it checked out THEN decide what to do. Go back and read my post #14 and #17.

 

Because I'm unemployed at the moment and I imagine shop isn't free.

 

Fixing what's wrong ain't gonna be free anyway. I don't see where a diagnosis will cost that much, if anything. You have a phone with paid-for service? CALL muffler shops and ask how much to check for excessive backpressure.