Iron Kissed by Patricia Briggs.

Iron Kissed by Patricia Briggs. Science Fiction. Pages 287. Series 3rd book. Mercy Thompson is a mechanic/walker. The policy with vampires used to be that they killed all walkers they came across. Now there are very few walkers around. Walkers are Native Americans who can turn into coyotes and have a bit of resistance to magic. Mercy never does know how to stay out of trouble so when a friend calls in a debt she runs off to help the fae. Soon her friend is in jail and she's getting chased by faery that want her dead because she just knows to much. Funny thing is the humans that are so harmless might just be the biggest problem out there.