ok so i had a wierd sound like marbles flying around in the motor. it happened when i floored it...above 7k....took it in to mazda...nothing...checked air filter, intake, heat shields, everyting down to the blinkers.....last night went to get gas and noticed gas cap was not clicked on it was just turned a half turn....long and the short aftger i tightened it down the sound went away...wtf

 

search for "marbles in a can"... it's an issue that's been around for awhile.

 

Before my engine busted a few months ago, my 8 has this "marbles in a can" sound for awhile as well.

I cannot say it is 100% related, but since I read lots of post regarding the "marbles in a can" sound recently, just want to give a heads up and keep alert everyone.

 

^
As did I but my fuel pump went out in the end

 

so after reading about these issues i still have no concrete description of what this is and more importantly why it is happening...

 

Did you make it to this thread? https://www.rx8club.com/canada-forum-35/noo-my-09-has-marbles-can-noise-miac-191483/

I like that one the best because it explains a little bit about the problem and more importantly........the fix and the part number that many people(not all) have had fix the issue.