Another thing. My (former) mechanic did the same thing you did.
He pulled all sorts of vacum hoses off and on and nothing changed, so he determined that there wasn't a vacum leak because nothing changed.
But, there was a vacum leak all along at the intake manifold seal. Which is why nothing happened when he pulled the vacum lines off.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".