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 regulator began the probe into Ford Bronco vehicles equipped with 2.7L EcoBoost engines in July 2022. The safety administration then expanded the investigation to include Ford Edge, F-150, Explorer and Lincoln Aviator and Nautilus vehicles from model years 2021 and 2022 that used 2.7L or 3.0L EcoBoost engines.

The agency suspected that the engines had a faulty valvetrain but Ford assessed that not all valves within the spike period are defective and that reported failures occurred in vehicles with low time in service, according to the report.

Most incidents reportedly occurred before 20,000 miles with more than half arising before 5,000 miles.

The agency said the results of its analysis primarily matched Ford’s assessment, implying that most failures with defective valves already happened, the report said.

Ford extends warranty for 90,000 recalled vehicles

Ford issued a recall in August for 90,736 vehicles equipped with "Nano" engines and produced between May 2021 to October 2021. On Monday the manufacture announced it would extend warranty coverage for the recalled vehicles for 10 years or 150,000 miles, whichever occurs first.

The Aug. 23 recall urged users to take subject vehicles to a Ford/Lincoln dealership for inspection of theirengine cycles' lifetime. Vehicles failing to meet the required threshold were further inspected for possible ineffective intake valves and offered an engine replacement.

Vehicles produced after October 2021 are equipped with a different intake valve material, according to Ford.

The National Highway Traffic Safety Administration confirmed that that there has been a decline of reported failures of faulty valve issue since November 2021.