Fuel line vibrates
2 Answers
Might be the idle air control motor is causing the vibration, or debris caught in the idle air control valve. This is assuming it's not engine vibration translating to the fuel line due to a broken mounting clip along the fuel line somewhere. You can disable the IAC circuit as a test. The engine idle RPM will be higher as a result. If the vibration goes away then you will know it was in the IAC. Google where your IAC is and unplug the harness connector to it.
I suppose this could be fuel pressure pulses from the fuel pump.