I've used the phrase "runs like a dog" to mean that my car is on its last legs and can't, sometimes, run anywhere near as fast as a dog can.
Can anyone shed light on where this meaning of the phrase came from?
The Google NGram viewer says that "work like a dog" is much more common.
Best Answer
According to the Online Slang Dictionary, one slang definition of dog is "something of poor quality or a poor performer."
It's sometimes used to refer specifically to a car of poor quality, as in The Dog and Lemon Guide. So to say a car runs like a dog means it runs like a bad car, in the same vein as "My car runs like a lemon" or "My car runs like a clunker."