Only a little. I have been trying to google it online and I am just coming up with the cat being sick. My cat is acting normal, right now he is purring and licking me/himself. So clearly he can still groom, he is only 3, he is an indoor cat, I am pretty sure he is not sick. I don't believe there are any kind of infections, and he does not smell of feces or urine. I can't really explain the smell, but it is almost a sour smell and I can only smell it when I put my face in his fur. My other cat does not smell at all. Any ideas?