Hi guys australian guy here

First up I have a Integra Vtir (gsr for all you american folk)

Ok so ive noticed recently after a long enough drive to warm the engine up my car starts to make a wierd sound (below)

Its only happened after this tank of fuel so im guessing it may be because my timing is advanced and I got a bad batch of fuel. It was ment to be 98 octane but yeah it may have been a bad batch.

Ive ran that tank down as much as I can (full throttle at low speeds in high gear, more air=more fuel ) and now its really not as bad anymore.

Anyone know if it would defo be the fuel?

Heres the sound, that was taken from my muffler tip itself so its not a hole in the exhaust.

http://www.youtube.com/watch?v=wJZsr...e=channel_page

Thanks,
Andrew