I've been having a similar problem. I have 3 keys and they all don't register a lock/unlock until about 2-5 feet away. This just now started happening about a week ago. I just put in a new car battery and the key fob batteries aren't that old.

I did have to pick up the new car battery from wal-mart when I was in a jam, so does anyone think that the quality of this battery may have an affect? It seems to be getting weaker even after just 2 months of use. Suggestions?