Several times this past week when I start the car in the morning I hear what sounds like a quick pop.

Seems to come from under the car.

Doesn't happen during later, in the day, starts or while driving.

Any ideas?

 

Mine does that sometimes too - just as the engine turns over, there is a quick pop. I figured out its an small intake backfire that is making the pop sound. Its normal for some engines.

2003 G35C, 6MT, DG/G, Aero/Nav/Premium
2002 Corvette Z06, Electron Blue/Black, headers, intake, exhaust, 380 rwhp

 

is that what the sound is