Sounds like a shorted egr. Ecm sees a short and shuts off to protect itself. P0405 is low voltage eger signal usually les than a volt. Check wiring to egr. Most likely a internal short in egr. Check all the following Scans codes and documents the freeze frame data in order to verify the problem.
Clears the engine codes and road tests the vehicle to verify whether the code comes back.
Visually checks the wiring and connections to the EGR control solenoid along with the EGR temperature sensor.
Disconnects and checks the EGR valve vacuum control solenoid for a short or open circuit in the solenoid.
Checks solenoid connection for corrosion in connection.
As for the p0200 thats injector related or ecm
Failed or failing injector
Open or shorted injector
Injector wiring harness has an open or short
Poor electrical connection
Faulty ECM
As for weak spark on cylinder 4 i would say bad coil or bad ground for icm/ over heating icm.
Seems like you have alot of electrical related issues. Before going to stir crazy go back over your wiring harnes and engine grounds. Could be as simple as insufficient ground of the block.