Dull grinding noise when accelerating

I have a 2003 Ford Focus Wagon which about 133,000 miles on it. When I accelerate I hear a dull grinding or scraping sound coming from the passenger side.

Any ideas as to what the problem could be?

Here’s a wild guess:

The passenger side is where the accessory drive belts and pulleys are. If a broken motor mount is allowing the engine to shift under acceleration one of the pulleys could be contacting something and making the noise.

Another possibility is a vibration in the exhaust system (loose heat shield?), but without being able to hear the noise it’s really hard to say.

Have you looked under the hood for any indication of scraping or grinding?