[Dancake]

Has your mpg dropped? An easy way to tell if it's an injector is to place the tip of a screwdriver on each injector and place your ear to the handle. This will amplify the noise enough for you to tell if you have a bad injector. A bad injector will be noticeably louder than the others. If it isn't the injectors then use the same technique to check for the source of the noise around the engine bay.