Hello. I am a newbie to this list. I have a 2006 MX5 with a noise problem.

When I am accelerating, typically in 5th or 6th gear to about 60 or 65 mph, I hear a knock or clacking sound (like knuckles against a table), always in groups of 2s, just under one second apart. My mechanic has driven and heard the sound but is unsure what it is. He does not detect anything specific with the engine. I had an aftermarket audio system put in to replace the original Bose system and, at first, I thought it might be that, but my audio guy does not think so and in any case, the sound occurs when the audio system is off as well as on. Notably, the sound seems to come from the right front of the interior. Indeed, at first, I thought it was coming from the passenger door speaker, but apparently, it is not.

This has been going on for over a year and is rather annoying, to say the least. I am bringing my vehicle in for regular servicing tomorrow and am hoping for some suggestions for my mechanic to explore.

Thank you for your help and guidance regarding this issue.