You know how in English sometimes "would like" can mean something like "used to like"? For example: "As a child, every morning when he arrived at school he would try to slip in by the side-entrance without the bullies noticing." "When I was younger, whenever I went to my grandma's, she would give me chocolate brownies." That way of using "would" can correspond to the imperfect tense in Portuguese (I believe - my Portuguese is intermediate, but it's basically a similar deal in a bunch of Romance languages). I don't think we'd often say "would like" using "would" in that way though. "Eu gostava" would be the imperfect tense, and "eu gostaria" the conditional tense, which is more like the usual way of using "would" in an if... would... construction. Maybe these examples could work: "What I thought of my mother's chocolate brownies depended on my mood that day. Whenever I was in a good mood, I would like them; whenever I was in a grumpy mood, I would despise them." --- use "eu gostava"? "If you added cinnamon to that hot chocolate, I would probably like it." --- use "eu gostaria"? "When I gave her the new chocolate drink she had never tried before, I knew she would like it" - use "gostaria" because it's the future in the past? i.e. I knew that she was going to like it. Things then get complicated when you need the subjunctive in Portuguese, but that's another story.

"Eu gostava" means you don't like it anymore, even though you did in the past. "Eu gostaria" means that if some condition happens, you'll like it. The Portuguese have the custom of using the verb tense "Eu gostava" with the same meaning as "Eu gostaria", but this practice is not so common in Brazil.