[cleszkie]

If the timing chain has been replaced in the past (as it appears to be), that increases the odds that a cam swap also happened, which could mean a cam profile that generates less vacuum. Judging by how clean the post on the cam that engages the cam gear is, I'd say that the cam was replaced. Remove the cam gear and see if the cam grind number is identified on the end of the cam. This should give you an idea of what vacuum the cam should be making.