Authorities tell Eyewitness News the man and woman, identified as 33-year-old Christina McCardell, were at a hotel.
While he was inside checking in at the Pearl Inn, McCardell slid over to the driver's seat and sped off in his vehicle.
Police say the man had a gun and when he saw her stealing the truck, he ran out of the lobby and fired at least four shots at her as she drove away.
A bullet hit McCardell in the leg, causing her to lose control and crash into a 63-year-old driver in a Toyota at the intersection of the South Sam Houston Parkway and Bellfort.
The driver, who was on her way to work, was pinned against a light pole.
She and McCardell were taken to the hospital. Both of them are expected to be okay.
Police say McCardell will be charged with auto theft.
RAW VIDEO: Surveillance video shows woman allegedly stealing truck
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