I haven't been driving my car lately since I have the interior out, but I do start it and let it warm up about once a week. Well today I started it and let it fully warm up, then I noticed a buzzing sound coming from around the passenger side fuel rail. The best I can describe it is that it sounded like a loud fly buzzing in a jar, it would come and go every few seconds, and when it happened the idle would drop a bit. Could this be a failing injector? I have always suspected one of them is leaky since my exhaust smells rich.