Is it the parking brake or the auto hold? I notice something that sounds like what you're describing on a cold start, but I think that it is either the parking brake or the auto hold system, as I only hear it right when I start to accelerate for the first time, and only very briefly. It actually sounds a lot like the sound that my previous cars would make when the collision avoidance system engaged, which further makes me think that it is the auto hold system.I've also heard a noise every now and again on a cold start. Mine isn't popping though, more like a grating sound. Almost sound like the fan blade is hitting the shroud. I'm hoping its just a tolerance issue, maybe the shroud is contracting enough to lessen the gap somewhere along its circumference and causing the fan blade to make contact. If that's the case, I'm thinking the affected area will eventually be 'grated' away and the problem will fix itself but will keep an eye on it. Anyone else experiencing anything similar?