P1404 Exhaust Gas Recirculation (EGR) Valve Pintle Stuck Open
P1404 Heated Catalyst Current too High During Heating (Bank 2) (BMW)
P1404 EGR Closed Position Performance (GM)
A new EGR valve (if you do need one) is about $80 according to one of the online GM parts stores.
Okay, so it depends fiercely upon the year. 97-99 with the 2.4 is about $200, the 3.4 is $150. 2000 and beyond is about $80 regardless of the year. So it's all about what year...