WASHINGTON The National Highway Traffic Safety Administration said on Monday it is upgrading and expanding its investigation into 708,000 Ford Motor sport utility vehicles over catastrophic engine failures tied to a faulty valve.

The agency says under normal driving conditions vehicles without warning may experience a loss of power due to catastrophic engine failure related to a potentially faulty valve in 2.7 L and 3.0 L EcoBoost engines.

The agency opened a preliminary evaluation in July 2022 into 25,000 vehicles and is now upgrading the probe to an engineering analysis, a required step before it could seek a recall.

(Reporting by David Shepardson, editing by Ed Osmond)