Oh, is it carcinogenic? I tried finding some published journal articles about it on Google just now and got too many news sites that don't link to their cited studies. I'm curious and will look at databases, but if you've got one off the top of your head, shoot it my way.
Looks like Coca-Cola has cleaned up their act, though Wikipedia says that 4-Methylimidazole is found in plenty of other commonly consumed food items as well.
Here's the article about the Coca-Cola thing--but I really wish I had found a nice, meaty journal article to actually read about this rather than secondhand news articles. Still looking to see the current state of things.