Someone suggested that code indicated DPFE may need replacing, but it's not cheap. Any other suggestions? I'm not a mechanic, but I'll try to do whatever I can to avoid the high costs at the dealership.
1999 Crown Victoria w/ 4.6L showing DTC P0430 - Catalyst System Efficiency Below Threshold (Bank 2). When this appeared, the car started having difficulty running at idle when the car was cool (would die and need restarting repeatedly). Once it warmed to normal operating temperature, the idling problem went away.