Thursday, March 13th, 2014 AT 10:56 PM
Car started making a loud metallic knocking noise under the hood, but only noticeable while idling; when I give it a bit of gas or start driving, the sound pretty much goes away. Come to a stop and it knocks again while idling {in Park or Drive}. Can't see anything wrong under the hood. Car seems to run OK, but haven't had it on the freeway since the knock started (just around town). Any ideas?

