cat eating feces

Question
I have a 5 year old male cat. He is not purebred, he's just a regular cat. He is overall very healthy. But, he does something that is very strange: from time to time, he eats his own feces & then vomits. We never catch him actually eating the feces, but when cleaning up the vomit it can be seen very clearly. Is this normal for cats? I know dogs sometimes eat feces, but I have never heard of cats doing it. Is it indicative of a health problem of some kind? I'm not even sure when he does it or how long after the eating he vomits. We have the automatic litter box, so his feces are not laying around exposed in the litter for very long. The LitterMaid cleans itself 10 minutes after he exits the box. Any light you can shed on this situation would be very much appreciated.
THANK YOU!

Answer
HI Leila,
I have not heard of a cat doing this, but have had many questions about dogs doing it.  I was going to suggest the LitterMaid, lol, then I read that you already have one!!  There is also a product called Forbid that you give your cat and it will make him not want to eat it anymore. If you cannot find it locally, go online and do a search for veterinary products and you should get some results where you can buy it.  It works!!  
I don't know why he does it, only that maybe it still has a fishy smell, who knows???
I hope this helps.
God Bless,
Becky