I couldn’t agree more with sdrealtor as well. ESPECIALLY if you are considering anywhere in 92101 or 92102. Go look at short sales or foreclosures in Mission Valley. Better yet if you are serious about making money off of rental property why are you considering San Diego at all? I have rental properties here but they have been places I lived in and then grew out of and simply never sold. I did make a purchase of one back in 02 and let it go in 07.
At any rate, there are considerably better opportunities out of state, or even within the county if you do your homework, or better yet have patience and wait.