Maggie Booth and her husband were driving along Leyland Lane on Saturday (December 18) when the man gestured at them in a panic, signalling for them to pull over.
Startled by the man's urgency, the couple stopped outside Windsor Close to see what the matter was and were shocked when he told them their car was on fire.
The couple scrambled out of the white Mercedes and moments later, the car was consumed by fire.
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"We didn't have a clue", said Maggie. "We got out of the car and within seconds the car went up in flames.
"We just want to thank him from the bottom of our hearts and so many other people who helped us when we were there."
In a picture taken at the scene minutes after the couple's dramatic escape, Maggie's Mercedes can be seen shrouded in a cloud of thick smoke.
In the chaotic aftermath of the fire, she didn't manage to find out the name of the eagle-eyed dog walker, whose quick-thinking might have saved her and her husband's lives.
"If anyone knows who it was we would really like to thank him because he saved our lives today," Maggie said in a Facebook post.
Following her Facebook appeal, she has managed to trace the man to thank him personally.
The Leyland fire crew were called to the scene to hose it down and said the Mercedes was "well alight" when they arrived.
A fire service spokesman said: "At 12.43pm on December 18, one fire engine from Leyland attended a vehicle fire on Windsor Close, Leyland.
"The incident involved one vehicle that was well alight on the roadway when the crew arrived.
"Firefighters used one hose reel to extinguish the fire. They were in attendance for approximately 50 minutes."
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