Those are probably fake files. Especially if your search returns thousands of results. For me it seems to come and go. I can do a search and get what I'd consider a normal amount of results(less than 1000) and they'll be good files. Then I'll do a search and get 4000 results(mostly all fake). So keep trying you should be able to find some good ones.
It's probably just coincidental that you've been having trouble with mp3s and not mpegs. Popular files tend to bring up more fake results.
See:
How to find music Fake files showing up in search results (Connecting for ages with many hosts & then Need More Sources when trying to download a file.).