A Brooklyn car mechanic taking an SUV out for a test drive lost control of the vehicle and plowed it into a couple sitting on their front porch enjoying the weather yesterday, police said.

Cops are now looking for the driver, who fled the scene after he barreled the GMC Yukon into the East New York yard on Dumont Street where Francisco Chavez was relaxing outside with his wife.

Cops said Chavez, believed to be in his 60s, suffered a broken leg. His wife was shaken up but not seriously injured.

“[Chavez] told me his leg was broken, and I could see the bone sticking out of his leg,’’ said neighbor Juan Rodriguez.