1999 Chevy Tahoe 2 dr 4x4 P0410

[dgholt]

My service engine light is on and when I checked the error code it brought up a P0410. My secondary air injection pump runs when I first start it up, but it doesn't seem to be getting enough vacuum to allow the air to blow through the valve by secondary air pump. I replaced the egr vacuum solenoid thinking it may be that, and also replaced the vacuum line thinking I may have had a leak but still keep tripping the code. Anyone with knowledge of this problem or prior experience you help would be much appreciated.