my 2000 Chevy Venture won't pass a smog test. the service engine light is on and the data trouble codes are:
P0507 - Idle Air Control System RPM Higher Than Expected
P0171 - System Too Lean

I just replaced the idle air control valve but the service engine light is still on. anyone have any ideas on what the problem could be and how to fix it?

 

also when i was replacing the idle air control valve, i had to remove a hose because it was in the way. the front end of the hose connects to a hole in the air intake plastic tubing, but i can't figure out where the other end of the hose plugs into because i can't see the back of the engine. anyone know what this hose is and where the other end plugs into?


here's another picture of the same hose circle in orange?

 

i went to the mechanic and they said i had a leak with a plenum gasket which is part of the upper intake gasket. the bad plenum gasket was causing the air too lean and idling higher than expected. the mechanic replaced the plenum gasket and the service engine light went away. i was able to pass a smog test and register the van.