Did you only replace the elbow fitting? It may also be split at that tubes other end. It attaches to a fitting in the intake air tube just in front of the intake of the turbo near a fitting with an electric sensor. The rubber vacuum elbow at that part is on the top, rear part and that end also disolves from oil.

I usually just bypass the original elbows and plastic tube altogether.

If that's OK, you'll need to have the code(s) checked and cleared, assuming the problem is solved. Vacuum leaks often trigger fuel trim or O2 sensor codes so that's possibly what they'll find. Double check all vacuum hoses too.