My Corolla with 17,000 has started making a sort of soft, moaning sound (hold the jokes please) when I take my foot off the gas. At first I thought it was the pedal itself, but I noticed if I pop my foot off it quickly, the noise continues for about one second.
I first noticed it about a month ago, but it has started doing it more frequently lately. Car is still under warranty, but I don't know if this is anything to bother with taking it in over.