So last week my father-in-law and I start working to change my fuel filter. Well for all of you who've done it after it's past due, you'll know how difficult it is to remove.

After replacing it, I decided to clean out the IAC valve. When I got the valve off, a bunch of little pellets fell out of it. Somewhere around a tablespoon full of black pellets and about the size of course sand.

I'm thinking they must have been some kind of carbon deposit, but I'm wondering what would have made them harden and collect so much.

Any ideas?

That is interesting. Never heard of that.

You got me on this one as well. I cleaned my IACV for the first time in 50k miles, and had a little carbon build-up on the end of the valve that extends into the throttle body, but that was all.

I was expecting build up similar to what I found in the throttle body when I cleaned it, but this looked like someone took a charcoal briquet and smashed it into course sand.

Anyways, just thought it was interesting to share with everyone.

I dunno, I don't run an IACV