I had a very similar experience on a one-way PDX-SJC. I was first given a car with Indiana license plates, but it reeked so much with smoke that my girlfriend immediately started sneezing. I exchange it and was given a New York plated one, which turned out to have severe safety issues: underinflated tires (remember the Explorers?) and windshield wipers so worn that you couldn't see through them. It also had 25,000+ miles.

I wrote in to let them know of the situation and got a form letter advising of their emergency assistance 800#. Next time instead of filling the tires myself I will call that number and have someone come out (at great expense to Hertz) so that they pay better attention next time.