I never had this problem till after I had my oil changed and tires rotated. There's a growling noise that only happens when you lightly press the gas pedal and only occurs between 20 mph and 45 mph. The noise is comes and goes, changes in volume from really quiet to loud, and lasts for a good few seconds to one second. I took it to my Kia dealer and was told it might be the exhaust, but they did research and performed an engine update thinking that would remedy the problem. It didn't and so I had to bring it back today and try to get the problem fixed. This time I had a specialist ride with me and every time I pointed the noise out to him he'd change what he thought it was from not hearing anything to normal engine noise to low rpms going through the exhaust and said it was normal. He also said that it happens on all Kia Fortes and I felt pretty much brushed it off. I've already had an advisor and a tech ride in it the first time hearing it and now having this other tech ride in it the second trip there saying nothing's wrong. If anyone else is also having this problem or know of what kind of solution there is I would greatly appreciate it as I'm fed up with Kia at the moment and plan on never buying another one in the future.