Key TakeawaysFord shares tumbled in premarket trading Thursday after the automaker reported quarterly earnings that came in below expectations and kept its full-year bottom-line outlook unchanged, as warranty costs continued to weigh on the company’s profitability.Since breaking out from a descending channel in late June, Ford shares continued trending higher for several weeks but have undergone a retracement in recent trading sessions leading into the carmaker’s quarterly results.Ford shares could attract ...