WASHINGTON - New passenger cars must have tire pressure monitoring systems in place by the 2008 model year, the government announced Thursday. To comply with the regulation, which has its roots in the Firestone tire recall of 2000, automakers most likely will attach tiny sensors to each wheel that will signal if a tire falls 25 percent below the recommended inflation pressure. If any one of the four tires is underinflated, the sensors set off a dashboard warning light. Automakers will begin implementing the technology in September. The National Highway Traffic Safety Administration estimates the upgrade will cost manufacturers between...