Gary Pittam performs a recall service on a Chevrolet Cobalt at Al Serra Chevrolet in Grand Blanc, Michigan, in this April 17 photo. General Motors Co. (GM), already locked in a public relations crisis because of a deadly ignition defect that has triggered the recall of 2.6 million vehicles, is now considered the worst big automaker to deal with, according to a new survey of top suppliers to the car industry in the United States. The annual survey, conducted by the automotive consultant group Planning Perspectives Inc., asks the industry’s biggest suppliers to rate their relationships with the six automakers that account for more than 85 percent of all light vehicle sales in the United States.SD-Agencies