quick question,

Today under hard acceloration, my engine made a noise like it had bad gas in it. Never had this before. I tried to reproduce it once more, but could not do it. What would cause this. It wasnt a pinging noise, sounded like a bunch of marles rattling ina can. Lasted only for a second

 

Hmmm.. maybe you hit something..small rock maybe?

 

and your definition of pinging would be.........

 

maybe part of your cat converter went bad, and broke apart, and tinged pinged out the exhaust.