Bernie Woodall and Joseph White

Ford Motor Co (F.N) and General Motors Co (GM.N) have worked all year to convince investors that they are no longer prisoners of the U.S. auto market cycle and have solid plans to fend off challenges from Silicon Valley interlopers.
 
 This week, Wall Street looked at the Detroit companies’ stronger-than-expected quarterly results and turned thumbs down.
 
 GM, the largest U.S. automaker, reported record third-quarter net income on Tuesday, but its shares have fallen nearly 5 percent since then.
 
 Ford shares sank more than 1 percent on Thursday, bringing their year-to-date decline to about 17 percent, or about $7 billion of the company’s market capitalization.