The National Highway Traffic Safety Administration says it has closed an investigation into reported performance issues with Ford’s 3.5-liter EcoBoost engine.
The agency opted not to issue a recall on the engine, of which approximately 360,000 were built in model years 2011-2013. Following 95 complaints of reduced engine power under heavy acceleration, NHTSA opened an investigation nearly a year ago. The agency says it has logged a total of 525 similar complaints, while Ford said it received nearly 4,000 more.
NHTSA and Ford determined the problem stemmed from cylinders misfiring as condensation built up in the charge air cooler matched to the turbochargers. In humid or rainy conditions, the misfiring triggered the ECU to disable those cylinders to protect the catalytic converter.
Through its own testing, Ford engineered a protective shield that prevented condensation from developing and causing the engine to misfire. It published a series of service bulletins detailing that dealers install the deflect shields onto the charge air cooler in affected vehicles.
The move avoided a formal recall.