White smoke coming from the exhaust.

[wparsons]

If it was the head gasket, the smoke would typically be worse when you're driving at higher revs, not when idling.

[Jason@DSG]

Originally Posted by wparsons

If it was the head gasket, the smoke would typically be worse when you're driving at higher revs, not when idling.

I have a video somewhere of my car at idle with a blown head gasket. It's insane how much smoke comes out once the car was warmed up.

As for this scenario, the OP's car seems to have a similar exhaust smoke like when the car is cold. The only thing I can think of is possibly some type of narrow-band sensor in the exhaust or intakeflow sensor that is making the car receive incorrect info. This would make the ECU run different air/fuel settings here and there possibly explaining the random white exhaust which isn't a constant

[wparsons]

Originally Posted by Jason@DSG

I have a video somewhere of my car at idle with a blown head gasket. It's insane how much smoke comes out once the car was warmed up.

I bet it smoked worse at higher RPM though... it can definitely smoke at idle.