Even as it pushes Apple to weaken the security on its iPhones, the US Federal Bureau of Investigation is warning car makers and owners that attackers have demonstrated more interest in finding ways to attack the computers that largely run current and older vehicles, and urging automakers to upgrade car firmware and otherwise tighten up security in vehicles. The warning came after exploits became public showing examples of how accelerators could be disabled, engines turned off, and various options like windshield speed and air conditioning adjusted remotely up to 10 miles away.