I have P0420 and P0171 set on my vehicle. While I am driving the vehicle, it drives fine but if I idle then it may or may not stall. During stopping at traffic light the vehicle pings/jerks and when I leave the light it seems that vehicle does not has full power it accelerates in pulses/jerks. Also sometimes I hear a continuous noise on startup. Has anyone seen this in their vehicle and what did you or a mechanic end up doing about it?