Try this, remove the vacuum line to the EGR valve & plugged the hose with a golf tee. If it's the EGR value that�s causing the problem the misfire will continue & means that the EGR valve is defective. If it continues to idle badly reconnect the vacuum line & remove the electrical connector for the EGR Vacuum Regulator (EVR) if the idle stays bad replace the EVR unit. However, if the idle get's better replace the Back Pressure Transducer (DPFE) unit. Hope it helps
