Bicycle Mechanics - possible slipping during cold weather rides?

I just purchased a 2006 Specialized Sirrus Sport and have noticed taht during cold weather the chain feels like it is popping in and out of gear, almost like a ghost shifting but also feels like the chain is slipping. I have sent the bike back to the place I have purchased it and they replaced the chain with a SRAM complete with a quick link and dumonde tech lube. They also adjusted the derailer and small adjustments to the derailure cables. The problem has all but gone away during riding even during uphill torquing, until the temp drops below 20ºF and I start to experience the popping again. Also, when I stop pedaling I can hear the chain "ding" the frame. I do understand that metal does contract in cold temps but this shouldn't cause these kind of problems. Would this be considered apart of the breakin process and disregard taking the bike back in to have adjustments? Any ideas? The last thing I want to do is continue taking the bike in for this problem and become one of those annoying, problem child customers.

I had this same problem a week ago on my bike. I solved it by oiling the freewheel with some chain oil. Your freewheel comes packed with grease, which thickens in low temps and can make the pawls stick. The chain oil seems to be working fine, though obviously it is not as durable a lube as grease. I have a beater bike so I don't care too much about my freewheel, but I do plan on putting a bit of oil in there every time I lube my chain.

I think what's going on here is that the pawls in the freehub don't spring up and engage as quickly when it's cold. And this isn't because of the temperature's effect on the metal - it's because of the temperature's effect on the grease in the freehub body. The grease gets harder, so the pawls don't pop up and engage as quickly. Hence chain oil, which is lighter, will "cut" some this harder grease and partially relieve the problem.

If my assessment here is correct, the slippage would mainly come after you'd been coasting for even a part of a pedal stroke. If it comes out of the blue when you've been pedaling circles without a break in the pedal stroke, then the problem is something else.

Thanks! I've payed closer attention to this during my rides home at 2am in cold weather. Since the bike is so new, less than 3 weeks, I had the bike shop repair it at no cost. They said either they will fix the problem or replace the hub at no cost to me since this problem has been occuring from day one of riding.
Again, thank you for the help.