I had a noise with my zetec ATX when I was coasting (release of accelerator). It sounded like light thumping. It was the engine mounts. The end of the transmission (can be seen from the driver side wheel well) was sitting on the fram of the car. Even after replacing the mounts I noticed that the space was only about a quarter of an inch.
I warn you the 4 mounts are expensive. Two are at 140 dollars each (aftermarket $120). Two other are 80 dollars each (aftermarket 70). Cost me $550 to replace total, labor was 2.5 hours. I used after market parts hope I did the right thing. I noticed that the aftermarket one was made in Korea(I was hoping that they would be the same OEM part without the ford label).