0401 Insufficient EGR Flow - This is typically not an EGR. it's the MAP sensor that is not seeing a change in airflow when the EGR opens. Check your MAP sensor, vacuum leaks and work your way back to teh EGR.
0305 cylinder 5 misfire. Check the coil, plug wire, plug and swap the plug wires at the coil for 2 and 5. If the misfire moves, it's the post of the coil, wire or plug. Don't dismiss that a plug may have cracked or been bruised up before the install.
Odd on the 1870 Take a read on this
http://www.sonnax.com/system/pdfs/12...pdf?1289926276