I say 2 feet of 5/64 inch vacuum hose will make your problem go way. Check the vacuum lines to the combi valves from the solenoid.

 

There are sooooooo many threads tackling this subject. Run away from that mechanic this is such a common problem with these cars he's either trying to

a.) rip you off royally
or
b.) has no idea what he's doing and is a far bigger risk to your car than a clogged Kombi valve or toasted SAI pump.

Removing the Kombi can be a byatch, might have to cut down an allen key to fit but the Kombi's are clearly accessible from the top of the engine without having to do more than remove the air box & move the expansion tank out of the way. Only part you can get is OEM & I believe they are from $225 - $300 a piece.

Or you can remove the somewhat useless SAI system & flash it from your ECU