It sounds like a thump from behind the front seats(the rear deck). When it thumps the radio will stop playing for about one second. I thought it might be the radio, it happens with the radio off. There is no consistancy to the noise, on two different 15 minute trips, it won’t happen on one and 5 times on the other.
Going to need a LOT more info.
Does it thump when taking off?
Hitting a bump?
Did you let the kid out of the trunk?
Remove everything from the car and trunk except yourself. If the thump goes away you have a big clue what’s causing it. Be sure to carefully inspect the trunck area, especially near the top of the rear struts, and the spare tire area, b/c there can be nooks and crannies that smal objects like golf balls can get to and cause this sort of noise. Under the seats of course. This theory doesn’t explain why the radio turns off, but that could be an independent problem.
Thank you for the response. The problem was a bad bose amp.
So the “thump” was coming from the speakers, a radio/amp electronic faulty was the cause of the sound? Interesting. Glad you got it fixed.