NHTSA to Probe Ford Engine Throttle Complaints

The National Highway Traffic Safety Administration is looking into more than 1,400 complaints that engines in 2009-2011 Ford and Mercury cars and crossovers may surge or unexpectedly switch to a low-rpm "limp home" mode.

The agency is assessing the scope of the issue, which could affect about 725,000 Ford Fusion and Mercury Milan sedans and Ford Escape and Mercury Mariner crossovers.

NHTSA opened the probe in response to a petition last October from the North Carolina Consumers Council, which reported two complaints.

The problem appears to be caused by an engine throttle body that sticks open or closed. Ford tells NHTSA that the issue, at least for early 2009 models, was a poorly manufactured circuit boards with throttle position sensor circuits that could break. A fracture would trigger a limp home mode that causes rough idle and/or limits engine speed to as little as 900 rpm.

Ford says Delphi Corp., which supplied the circuit boards, fixed the flawed production process in late 2009. But NHTSA has since received 59 complaints about similar engine problems in 2010-2011 Fusion cars. The agency notes that the frequency of complaints appears to be increasing.