In my webmaster tools, I'm viewing the Diagnostics - Content Analysis... I have an e-commerce site selling automotive parts. Many of them have the same description, just a different title because it's the same part listed for different years and models of cars.

I'm looking at these diagnostics and it shows I have 187 duplicate meta descriptions and 189 duplicate title tags. Is this hurting my ranking with google? I also see it shows I have 1 short meta description. I think I can figure that part out but the meta descriptions and title tags... that kind of worries me.

Should it???

It is definitely not doing you any good.
Think about your website as a library and each page is a book. Would you recommend a library to a friend where different books as the same description and/or title?

I think you get the idea.

Try to make different descriptions for each page...at least using different phrases / words / texts or using different pieces of the info you have