The fuel pump module is necessary so that if there's a crash, it can turn off the fuel pump. It's a safety thing, so don't just bypass it. Replace it if it's not working.
There are two significant problems. First is the PTU. Ford's recommendation that they never service the fluid makes them all fail, most before 150k miles. The second problem is with the 3.5L V6. They put the water pump inside the engine, driven by the timing chain. Super fun to replace. Other than those two, it's a decent car. Oh yeah, and the transmission filter is not serviceable.
