An investigation into over 411,000 Ford and Lincoln SUVs and pickup trucks that had a potential engine defect that caused the vehicles to lose power has been closed, the National Highway Traffic Safety Administration announced in a report Monday.

The U.S. government’s auto safety regulator has ended a 2 1/2-year investigation into Ford engine failures after the company replaced engines or extended the warranty on some vehicles. The National Highway Traffic Safety Administration says in documents posted Monday on its website that its analysis traced the problem to intake valves that can fracture inside some 2.

Ford Motor on Monday reported an about 15% rise in U.S. auto sales during October from a year earlier, aided by demand for its F-series trucks and hybrid models. Sales of its trucks, which include the popular F-150 model,