I have as well experienced this, My buddy has a 02 SE and everytime he stepped on it we could smell it, He would call it the "smell of speed' lol, take in mind his car has over 220km and he drives it hard. I have a 04 SE with 121km and everytime I step on the gas I can smell it but not as intense as the 02 SE. I also have a 96 infiniti i30 130km and the same thing applies but not as strong as either cars above.

Both maximas take premium gas,the "cat" could be a factor as well on the 02 Se, the 04 is good shape and couldn't see it being the cat yet. The 96 infiniti doesn't take premium and is in as good as shape as the 04 or better, I have been behind my buddys car and other cars on the street, and when they let out I can smell it.

Premium gas, Cat, How you drive? are all good factors I dunno...