My E 350 Ford has P1443 and PO411

Hi there, I have a e350, 7.5 engine. the codes P1443 and PO411 keep coming up. I have looked over all the valves and hoses, repaired a air leak in the head / exhaust manifold. I checked the air pump. every thing looks good. I unhook the neg, then take a ride for 20+ miles then the engine light comes on. After I take it for a run,when the engine is hot. I hear a huming noise coming from the left front (facing the engine) a loud huming. when the engine is cool no such noise. what can I check next , need help Robert