This is a sneaky problem that happens when the fuel pump starts to degrade. I have a 2000 cougar 2.5L and probably did it to myself. I was down to about one gallon in the tank and was gassing it hard going throug a turn and it stumbled bad, pump sucking air. In the month or so since then it would start to fail at 4 to 5 thousand RPM, at first only in second gear, (figure that one out) then more and more in other gears where it would just float with no accelleration. finally, it would die like you turned off the key if you floored it at that RPM. This was always with less than 1/4 tank of fuel. I diagnosed it myself searching the forum here, then asked my dealer (Excellent dealer in Danville, PA) and he said he had seen it before, and that it made them crazy the first time they had seen it. I was lucky, Car still under warranty at 30,000 miles. This is what you need almost guaranteed, I think pumps are about $160, and on a Contour, you don't have to drop the tank, unlike my Cougar.
