A blonde pushes her BMW into a gas station.

She approaches the mechanic and tells him her car just died.

The mechanic spends a few minutes working on the car and gets it working smoothly again.

The blond looks at the mechanic and says, "So, what's the story?"

The mechanic replies, "Just crap in the carburettor."

In a state of amazement she answers, "How often do I have to do that?"