SOS: Burning Smell

So I get into my car this morning and everything is running fine. Right when I pull out onto the road I notice a burning smell that smelled like burning leaves. It took me a long time to figure out that the smell was coming from my vents. It's like a very salty burning smell. Doesn't really smell of chemical, rubber, or oil... just a salty smell that closely resembles burning leaves. All of my fluid checks out fine and I don't have a dead animal stuffed in my engine or wheel wells. The car seems to be running fine. It revs smooth, it doesn't smoke, and as far as I can tell it's in good order. It does it with the heat on or off. Originally when I was driving to work I had the heat on, but I turned it off on the way home and the smell was still present. Heat guage checks out fine, also. I was sniffing around my engine and the smell doesn't seem to be present, only inside the car. Can I get a WTF? Also, my pre-cat was replaced probably around 3-4k miles ago, so that shouldn't be the problem.

03 spec v, btw

burning smell? are you sure it doesnt smell like rotten eggs? if its rotten eggs, then its your catalatic converter itself, otherwise if its 'sweet' its your ehad gasket. im pretty sure it might be the catalytic converter starting to go bad, as i have that same problem occasionally. but since ive started to put in premium fuel into the sentra, like your suppost to i guess, i havent gotten that smell. ik what your talkin about. soon your check engine light will come on and say you need an o2 sensor. eventually.

Eh.. I just had my cat replaced about 3-4 k miles ago. I really hope it's not that, but I did smell rotten eggs not too long ago. I knew that was coming from my cat, but I wasn't sure if it could go bad so soon. I do use premium, though. My car is such a lemon...

apparently so. that sucks so much. at least you are learning your car a bit more each day. i guess you could say your sentra is almost like a dsm....lol. its not the pre-cat on the header, its the actual cat. i believe the spec-v has 3 cats on it. i know that i have 1(lucky me). i was cheap and used regualar 87. sure the car ran fine, but then it started to run a bit choppy. put in some synergen oil treatment, valvoline fuel system treatment with 87 octane gas, and i havent had that problem since. the premium does help with the choppiness if youw ant to call it that. gas milage has also improved drasticlly.

btw, i thought it was your pre-cat that went out? most likely its one of your O2 sensors going out. just do a check on those and you should be fine. the engine code for the bank 1 sensor will appear in about 500 miles or so i think.
hope i was some kind of help.

Yeah, it was the precat that was replaced, but when I did have it replaced Nissan told me that it wasn't really a precat, infact it's pretty much the main one. They said the other one acts mostly as a resonator. Anyway, I drove it with the heat off for a while and the smell faded away. The more and more I thought about it, I had smelled that smell, but it was always so faint that I just assumed it was the heater. I turned the heater on later last night and I smelled the faint smell as usual when I first turned it on and then it faded out. The smell is completely gone now. I'm wondering if it's just something that burned up in my heat.. hell, I dunno, but I'm pretty sure it's not that cat smell. As long as it's not stinking I don't care anyway. The car is running great. However, one of these days I'm going to get a hotshot header and say goodbye to the cat... someday :(. I almost wish I would have just saved an extra hundred and bought that instead of the Nismo CIA.