As a federal investigation into a series of crashes expands, a mother is sharing the quick thinking that likely saved her life and that of her young son.

KNXV, our Scripps station in Phoenix, first highlighted a crash that killed a 17-year-old Arizona girl early this year.

The National Highway Traffic Safety Administration has since confirmed that it's opened an investigation into 730,000 model year 2002-2004 Ford Escapes and Mazda Tributes with three-liter, six-cylinder engines whose throttles may stick and could lead to a crash.

The federal investigation is focusing on "the potential failure of the throttle to return to idle when the accelerator pedal has been released in certain Ford Escape and Mazda Tribute vehicles."

The agency said that it has found 99 complaints about the problem, including 13 crashes, nine injuries and one death.

Estee Piehl was driving her 6-year-old son to soccer practice in Aurora, Colo., in April 2010 when she hit the accelerator in her 2004 Ford Escape to change lanes.

But when she let her foot off the gas, she said her car sped up instead of slowing down.

"(I told my son), 'Carson, mommy can't stop the car. Carson, mommy is trying to stop the car. I'm trying, but I can't stop the car right now,'" Piehl told our Scripps station KMGH in Denver. "The only thing he said is, 'Mommy, something's burning.'"

The smell of burning was Piehl with both feet slammed on her brakes.

"(I had to decide) whether to slam into the back of the cars in front of me going about 65 mph, or swerve into the continuing traffic," she said. "Literally, just by the grace of God, there was a left-hand turn lane that was open, so I was able to get over."

Piehl was able to slow the car down to 55 mph when she remembered the only thing experts say drivers can do to stop a runaway car -- put it into neutral.

She said she's glad an experienced driver was behind the wheel.

"When this happened to me, I specifically said, if this had been a teenager driving that car, they probably would have died," Piehl said. "It's a miracle that we escaped."

Scripps investigators found that Ford had issued a safety recall involving the accelerator cable on 2002-2004 Escapes in December 2004, telling owners that the problem could cause "elevated engine speeds" and even a "vehicle crash."

Ten months later, Ford sent out an update to that repair to dealers -- but not Ford owners.

In the documents sent to dealers, Ford wrote that the reason for the update is "to inform dealers that updated illustrations and a warning have been added to the technical instructions … to help prevent damage to the speed control cable while performing the accelerator cable replacement procedure."

One attachment says "Caution" and shows a "CORRECT" and two "INCORRECT" illustrations involving removing the accelerator cable.

The update went to dealers in October 2005, 10 months after the recall was first announced. Records show that by that time, more than 300,000 of the affected Escapes had already been repaired.

Those owners had their SUVs repaired without the new warning and instructions from Ford.

NHTSA's summary of its investigation highlights the updated repair instructions, saying “some of the complaints also allege that the failures may have been related to repairs performed as part of safety recalls initiated in 2004.”

The agency said its investigation will "assess the scope, frequency and safety-related consequences of the alleged defect."

Piehl's is one of the 99 complaints cited in NHTSA's investigation. She said she's still amazed that she and her son survived the incident.

"I'm just grateful that he's going into third grade next year," she said. "We lived through it."

More Information: Ford Motor Company Statement