Humming noise from front right

[lahalte]

I have a 2000 Boxster with 42,000 miles.There is an intermitent humming noise in the right front section.It usually happens cruising or turning hard right.I thought it could be bearings but what mixes me up is when I am cruising*40mph or so* and it happens I just lift my foot off the gas pedal very gently without slowing and the noise stops.To come back again.Sometimes it does not do it after driving for awhile.I was thinking of the fuel pump but why would it do it on a right turn only.My mecanic does not know and can't figure it out.It does not seem to get worst but I hate noise that I cannot identify.Any suggestions