96 f150 with 4.9 inline 6. truck had been sitting for transmission repair and now that it is all back together, I took it out and check engine light came on after awhile. the codes are P0401 - EGR Flow Insufficient and the 2nd code was P0411- Secondary air injection system incorrect flow. Can anyone tell me how to fix these? I reset codes and they came back on the next day. is the egr valve just need replaced? never heard of the secondary air injection system. any diagnostics i can do to check and determine what is throwing the codes? thanks

 

Insufficient EGR flow is caused by anything that is inhibiting the EGR. The EGR valve is not opening when needed or something is plugged up between the EGR and the intake.

Secondary air injection is the Thermactor smog pump. Is the belt on it and is it turning? If so, something is blocking flow or it's just dumping.