Vibration after changing camshaft position sensor

My 2001 325i auto had a very smooth idle before I changed the exhaust camshaft position sensor. I had the service engine light for this sensor but it ran and sounded great. I just replaced the sensor and cleared the code. When I started it the car had a very strong vibration and rattled very loudly. This occurs when the car idles at about 600 rpm. If I give it a little gas it goes away. I don't understand what changed when I replaced the sensor. Any ideas on what could be causing this? Thanks in advance for any help



Kene