'08 When barely given gas, car stalls

Example, when I take off from standing still, and accelerate normally, the car behaves right. But if I am creeping along as in stop and go traffic, or when carefully backing out of a parking stall, I am just barely giving it gas and it starts to stall. Kind of like when driving a manual transmission, lettign the clutch out and not giving enough gas. I took it to the dealer, but they could not come up with anything