The young pup, which has been named Kia, was left inside a suburban that was towed to a Kansas City impound lot on April 8.
Officials believe Kia survived by eating trash in a McDonald's bag and some old cigars that were left in the car. The terrier and schnauzer mix didn't have access to water.
Fortunately, a lot employee finally spotted Kia lying on the dashboard and called for help. Besides being dehydrated and underweight, the puppy is expected to survive.
Officials think the cool, rainy spring weather helped save her life because it wasn't so hot.
Kansas City Animal Control is using the impounded suburban's license plates to try and track down the owners. If they can find them, investigators say they'll charge them with neglect.
Kia will remain in foster care until she's healthy enough to be adopted.
(The Associated Press contributed to this story.)