If all else fails with the tap, you may need a shock arrestor, especially if the tap is at the end of a long pipe run. Sometimes just a different type of tap design with the pipework you have will cause the jumper to vibrate, it happens.
Something like a Watts Micron Shock Arrestor,
http://www.lunns.net/ , usually around £20 inc. might do the trick.
Washing machines etc are usual culprits for causing a shock with a sudden shut off.
If it's a vibration then it's often inadequate pipe supports.