My digital multimeter starts fluctuating while I bring it near to my started bike even if the probes are not connected to any where .I can't read any value during that time.Therefore I cannot check my bike electrical circuit.My multimeter shows correct values when I connect to home ac supply and it shows correct reading.When I checked voltage on battery,it is showing correct value.It has problem only when I bring it near to my started bike.What could be the reason?Is my multimeter faulty?