Generally speaking, Consumer Reports has been in love with the Tesla Model S, recently touting that the ultra-quick, all-wheel-drive P85D was such a good car it broke the organization's rating system. But now, it's warning would-be buyers that those awesome cars might not be particularly reliable.

CR says that it received responses from about 1,400 Tesla owners in its annual reliability survey, using that data to project a "worse-than-average overall problem rate" for new buyers over the lifespan of the vehicle. As a result, CR is pulling its coveted "recommended" rating for the Model S.

What's going wrong with the cars that are on the road, exactly? Sounds like CR is hearing about lots of things, ranging from the drive motors to the giant touchscreen in the center stack; 2013 models in particular are getting dinged for their drivetrains. They note that all of this should still be covered under Tesla's warranty — but obviously, a car that doesn't break is better than a car that breaks under warranty.

It's unclear whether CR's testing will have any real-world impact on Tesla's sales, but investors have been quick to react, sending the company's stock about 10 percent lower today.

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