Default What identifying info is sent with stock browser to websites?

A friend of mine said your phone number is among the info sent out to sites. The thing that got me wondering was looking for auto parts. I'd enter my year make model into one site for a search and that info also showed up on another parts site I had never visited. I have forms turned off in browser. I would search amazon for things, and even when I fully signed out after buying something, cleared all private data in browser with an about:blank start page, and used a app cache cleaner, they still remembered what I ran searches on. Even when all private data is cleared in browser, cache cleaner reports there's still data there 128k+ to be flushed out. Anyone have more knowledge on this subject and possible solutions?