2006 LS focus, wup wup wup sound front left.

[prydey]

Wife mentioned this new noise yesterday. I jumped in this morning to drop my daughter to school and there is a wup wup wup sound from the front left (i think) which does increase in rhythm with car speed.

What i found though, was that it was only there for the first few minutes before eventually fading away. School is only about 5km away and by the time i was on the return journey it had gone. Well, it had become inaudible from the cabin anyway.

I was thinking wheel bearing but this is normally more constant and grumbly sounding i thought.

There is no vibration associated with it, so its not like a flat spot on a tyre from sitting around. Car gets driven everyday as well.

any ideas?