If you really believe it's an engine mount, it should be easy to spot. Get under the vehicle with a pry bar, and pry on the engine part of the mount. If the rubber is severed (or missing), and the inner component is rapping against or sitting on the outer component, it should be obvious. I'm still skeptical this is the problem, because engine mount failures are not typical problem with these vehicles. Modern engine mounts are failsafe, the engine/transaxle can not get loose from the mount retainer, only rattle against it, and this is not common. I'd be more suspicious that there's a loose or broken exhaust pipe or hanger.