We have a Ford Focus, 2005. There is no problem during the summer, but when winter comes the accelerator will begin sticking. When my wife leaves for work it will be fine, but down the road, 3 to 15 miles the accelerator pedal will begin to stick, bad enough to make driving scary. My guess is that it is the cold that affects it. I've had it happen to me and it is a problem. We have to press hard to make it go (slowing down is not a problem) but pressing hard it will break free and speed up too fast.
There is nothing in the way of the pedal and we have taken it to two mechanics and neither have been able to solve the problem. I had the last mechanic put in a new cable thinking there might be moisture in the old cable, it did not help.