07 Malibu front end rattle

Ive got an 07 Malibu ls. For quite some time now I have had this frt end noise. Its a tapping rattling noise on fine bumps. Here is the strange thing. It only happens in the winter and then only for a while when I start driving. It kinda goes away as I keep going. When its very cold it doesnt quite go away but gets lots less as the car is driven for a while. Ive checked everything in the front end including sway bar links. Ive made sure the brake calipers arent loose. Ive had it checked out at a reputable shop. Of course as soon as the car is inside a warm shop, it wouldnt make the noise anyways. They have not been able to pinpoint it either. Any body else had this? What was the solution?

Tough diagnosis from here, upper strut mounts are nortorious on these cars.

Intermediate steering shaft is known to clunk too.