The Toyota sudden acceleration debacle may be a thing of the past, but one U.S. Senator thinks the government investigation is worth another look. Sen. Charles E. Grassley claims the National Highway Traffic Safety Administration, along with NASA, may have let what he calls a “serious issue” fall through the cracks. In a letter sent to NHSTA administrator David Strickland, Grassley raised questions about the investigation, asking whether vehicles were tested for a very serious defect called “tin whiskers,” reports the Los Angeles Times. Tin whiskers, as described in a NASA report, are “electronically conductive, crystalline structures of tin that...