Don't fret the 'soft' elbow yet. Erase the current code and see if it comes back now that the vacuum leak has been fixed.

The elbow could be one of many, check the vacuum lines at the air filter box, there are a couple of them. If those elbows look good, then check the elbows close to the vacuum tree and follow those vacuum lines so you can look at more elbows. Each elbow is less than $3, even at a dealer.

Just to compound matters, my car is also throwing a code related to the rear O2 sensor. My problem might be an exhaust leak or air entering the SAS valve at the exhaust.