U.S. regulators close Ford F-150 probe without request for recall

U.S. safety regulators said on Friday they have closed an investigation into complaints of reduced power in Ford F-150 pickup trucks, stopping short of requesting a recall.

Ford came up with a protective shield that kept condensation from developing to the point that it caused the engine to misfire in nearly all of F-150s it tested. Dealers were informed through a series of technical service bulletins, and NHTSA was satisfied that the problem was solved without Ford conducting a recall.

Last May, the National Highway Traffic Safety Administration opened an investigation into F-150 pickups from model years 2011 to 2013, which accounted for about 360,000 vehicles made by Ford Motor Co. Each of the pickup trucks has a 3.5-liter EcoBoost engine.

NHTSA received 525 complaints and Ford informed NHTSA of 3,731 more that the company received. Nearly 19,000 warranty claims may have involved the issue. No injuries, or crashes were reported to Ford or NHTSA.

During the investigation, Ford told NHTSA that a misfire could occur in its 3.5-liter EcoBoost engines which have twin turbochargers under significantly humid and rainy conditions because condensation could form, leading to the misfire of up to three cylinders.

As it does when it closes an investigation, NHTSA reserved the right to seek a recall of the affected vehicles in the future.