After nailing the throttle to overtake/make progress once out of urban speed limits I often notice a rotten egg/cat converter smell once I ease off.

Anyone else had this happen ? I've got a MY99. Is it possible that there's a leak, or could some of the gas near the cat is 'blowing back' somehow into the engine bay and through the vents ?

I'm positive it's not a combination of my lunch and accelerative forces squeezing my bowels and causing the smell.