334-pull the EGR valve off, and clean it. You can clean the pintle with some mineral spirits, a small screwdriver to get the crusty stuff off. Takes a while. Or replace it but they are not inexpensive.
224-check your SPOUT and it's connector. Remove the SPOUT and then clean the connection.
998-you'll get that if you have a major malfunction.
The coil code should be 215 or 216 by the wording, however you've got it as 224 (which is IDM code).
Once those easy things are taken care of, clear the codes and start over. Go for a drive if possible. Do the codes come back? If the 998 and 224 come back, look very closely at your wiring between the EEC and the engine; this includes removal and cleaning of the main engine harness connectors. Similar to the 5.0 "salt and pepper shakers", disconnect them, clean, repair the pins, then reconnect.