General Motors is recalling more cars for problems with ignition switches. The latest involves more than half a million Chevrolet Camaros from the 2010 to 2014 model years.

GM says a driver's knee can bump the key and knock the switch out of the "run" position, causing an engine stall.

That knocks out power steering and brakes and could cause drivers to lose control.

GM says it knows of three crashes and four minor injuries from the problem.