HELPPPPPPPP Check Engine Light ON, I need help bad Options

[Havok1997GT]

Guys im lost with this one and i need help with this.

Ive got a check engine light on thats is bring up this code P0401, Low Air Flow on EGR

I pulled the possible issues with this error and this is what i got

1.Blocked Passage on EGR (Which i have already cleaned out the Intake so thats not the problem)
2.Failed EGR Value( my Tech checked this when doing the cleaning and he said it pulled fine, but i dont know if its possible for it to pass tests and still be broken)
3. EGR Solenoid Faulty( Im assuming they mean the EGR Vacuum Solenoid)
4.Failed EGR Pressure sensor where applicable( not sure what they mean )
5.Failed EGR Postition sensor where applicable(not sure what they mean)
and im not even sure we have the last 2 on our cars because i cant find those parts for Celis anywhere.

The only thing i have left is the EGR Vacuum Solenoid or the Air Charge Sensor. These are the only things left that i can think of that could be causeing this problem.
If you guys have any input or know something im missing please let me know. its like $100 bucks for those 2 parts so i dont think its going to hurt to get them both and just do it. But im low on funding and cant do much more after this for a while. inspections out on my car so that why im in a rush to fix this problem. Any help would be great.

Thanks