The National Highway Traffic Safety Administration has opened an investigation into whether nearly 1 million General Motors vehicles may have faulty gas gauges.
"Consumers have reported incidents of inaccurate and random fuel level reading while driving, resulting in the vehicle running out of fuel and causing vehicle stall with no restart," NHTSA investigators said in their formal document opening the probe.
GM spokesman Alan Adler said the Detroit automaker planned to "work with NHTSA and was cooperating in the investigation."
The agency estimates 865,000 vehicles could be affected, and NHTSA said it has received "668 complaints alleging inaccurate fuel gauge reading while driving in model year 2005-07 Chevrolet Trailblazer, GMC Envoy, Buick Rainier, and Saab 9-7x vehicles."
Of those complaints, 58 involved stalls, and 43 were stalls in which a driver specifically reported that it was "because the fuel level reading indicated more fuel availability than what is actually in the fuel tank."
NHTSA said at least one crash allegedly took place when a vehicle ran out of gas, when it "stalled while exiting the interstate, became disabled, and was struck from behind."
The safety agency said the complaints they were receiving showed "an apparent increasing trend" of the problem, with "most complaints received within the past year."
What NHTSA terms a preliminary evaluation has been opened this week "to assess the scope, frequency and potential safety consequences associated with the alleged defect."
NHTSA spokeswoman Karen Aldana told the Detroit Free Press there is "no set timetable" for how long the initial phase of the investigation could take. She said government officials would seek information from GM and ultimately decide whether to elevate the investigation into what's known as an engineering analysis.
Aldana declined to provide more specific details on the cases involved.
GM's Adler said the Detroit automaker had received NHTSA's formal notification document about the preliminary probe, but had not yet received detailed questions from the agency about the potential gas gauge problem. He said those would likely be sent to GM by the government within the next couple of weeks.