Among Detroit’s Big Three, Ford Motor Co. looks to be in the best shape. But sometimes, even when you think you’re in the clear, you’re not. (At least in litigation.) That’s what happened to Ford last week in Oklahoma, where the state’s Supreme Court reinstated a nationwide class action against Ford and auto parts maker Williams Controls (pdf) that had been tossed by an intermediate appellate court. The class, which includes an estimated 300,000 to 500,000 members, contends that certain models of Ford Super Duty pickup trucks and Expedition sport utility vehicles contain faulty accelerator pedals, causing the trucks to idle rather than accelerate when drivers step on the gas.

The case, which was first filed in 2004, alleges breach of warranty, negligence and product liability. The trial court certified a nationwide class in 2007, but last year the Oklahoma Court of Civil Appeals reversed the lower court. In reinstating the case, the Oklahoma Supreme Court found that the trial court did not abuse its discretion in certifying a class on the breach of warranty claims. It declined to affirm class certification on negligence or product liability claims.