Occasionally when waiting at a traffic light i'll notice a tapping sound from the engine bay. The tapping is pretty random as it'll fluctuate randomly from slow to fast in repetition. It sounds like it's coming from the center or passenger area, but it's hard to pinpoint from inside, and it's not extremely audible from the outside. I think it goes away once i start accelerating, either that or i just can't hear it over the exhaust sound. I've also been struggling with exhaust leaks, and am wondering if it's simply an exhaust component tapping against something else, or something else? Thoughts?
Try listening harder with the car parked and on. My celica vibrates everywhere so it may just be a line tapping something hard. Make sure the sound isnt coming from your heads. Then move to the fans and belts infront. I doubt it has to do with ur exhaust but uou could also jack the car up in front while running and look to see if anything is vibrating and do the same in the rear. My wifes exhaust used to tap in the rear becuase of the tow hitch under it and it sounded like it was upfront. while driving it was silent.
I've also heard that fuel injectors can tap. I thought my Police Interceptor Crown Vic had a bad timing chain....it was the injectors. :rofl:
Its possible for the downpipe to rattle against a couple things. If I had to guess its the downpipe rattling against the support that it is supposed to be bolted to. In addition, it is also possible for the intermediate pipe to vibrate against the rear diff support. Also possible, depending on length of exhaust hangers for aftermarket mufflers to vibrate against the shielding.