NEW ORLEANS, La. — Consumer-rights law firm Hagens Berman filed this week a proposed class-action lawsuit against Ford Motor Co., alleging that the company’s Ford F-150 trucks contain a dangerous safety defect that causes the vehicles to shake violently, shudder and stall when attempting to accelerate.

The 36-page complaint, filed in the U.S. District Court for the Eastern District of Louisiana, quotes more than 20 F-150 owners who claim that their vehicles suffered from the defect, which attorneys believe is caused by a flaw in Ford’s Charge Air Cooler (CAC) system. The complaint alleges that the system, which is designed to cool air before it reaches the engine, causes condensation to build up inside the air intake tube, especially in more humid climates.

Attorneys said they believe that moisture moves into the engine when drivers accelerate, causing the vehicle to shudder. In severe cases, the F-150’s computer system senses the danger and forces the vehicle into “limp mode” to prevent damage, the complaint alleges.

“This is a significant defect, and one that involves a life-safety issue,” said Steve Berman, managing partner of Hagens Berman and attorney for the proposed class. “Before we began our investigation, we reviewed the reports of many owners who told us harrowing stories of narrowly avoiding what could have been fatal crashes when their F150 stalled while attempting to pass or change lanes in busy freeway traffic.”

The suit claims that Ford is completely aware of the issue, and has gone as far as to warn dealers in a secret memo, noting that vehicles may “stumble and/or misfire on hard acceleration after an extended drive at highway speeds during high humid or damp conditions.”

Steve Berman currently serves as co-lead counsel for the economic loss class in the sudden, unintended acceleration lawsuit brought against Toyota. That case has resulted in a proposed settlement valued at up to $1.4 billion, the largest automotive defect settlement in history.

The lawsuit against Ford seeks to provide compensation to all current or former owners and/or lessees of model-year 2011-2012 Ford F-150 vehicles.