Welcome to the Q&A Forum

I'm not an expert so forgive me if I'm wrong. I am doing the same thing with my search results car / auto. From what I know Google recognizes synonyms and acknowledges them. What I did is target car as the main keyword and in the first paragraph or somewhere close to the top I use the term auto. When you do a search in the SERPS I rank for both car and auto terms (not exactly the same position but not a big discrepancy). The only difference is what Google bolds in the SERPS description. If I search car it will bold my page title with the term car and when I search auto it bolds my description with the word auto in it.

Again I am no expert and there may be better or more SEO friendly ways but this is how I went about it.

My site is set up with a mobile website and after running the on page SEO report on moz it is returning multiple errors for duplicate title tags and duplicate content all related to the mobile website being a direct reflection of the main site.

I want to know if this is really an issue. I'm sure Google actually knows the difference between my main site and the mobile version. Do I really need to go through each individual mobile page and change each page title and modify all the content? I really would like to avoid doing this but at the same time would like to fully optimize my site. Any advice is appreciated.