Could be the F125 switch as others have said, but the car hasn't been used for a while, which could indicate something else. IF a scan doesn't show a fault, don't panic.
I had this exact problem as you describe when I bought mine 18-months ago, and cured it with a new battery after three weeks of ownership. Since then, it hasn't put a foot wrong.
I figured the battery charge wasn't enough for the sensitive ECU - no matter how often I drove the car. I have only done 5,000 miles in that 18-months, with the car laid-up for 6-months at one point... Problem never re-appeared
