need help

i have a 2000 plymouth neon an when i have the heater turned on u get a exhaust smell from the vents anyone have any idea what the cause of this is?

Has it been awhile since you turned the heater on? It will give you a rather strong smell at first, but then should go away.

umm the car was sitting on the lot for atleast 2 months before i bought it. i cant really smell it its my gf that says she can smell this smell and that it gives her a head ache, i had my father drive the car and he couldnt smell anything either. the biggest problem i have is the check engine light came on an the code is for catalist inefficecey ( i know i spelled that wrong) i also have the fuse light on in the dash and i cant find any blown fuses i have read other posts an looked for the things ppl found wrong but nothing seems to help!!.. umm is the catalist code a bad converter? the guy i bought the car from is trying to tell me that its a bad o2 sensor? but idk.. any help would be great. also one more thing will a srt4 hood and bumper fit on a 2000 neon?

Try and get the "P" code to narrow down the code. It could be a bad O2 sensor or a bad cat converter.

I don't know if the SRT stuff will be a perfect fit, but may fit.

well i found out i dont have a bad o2 sensor or a bad cat. converter where the down pipe hooks to the header there is a gasket that is bad i had the car up on a lift today ( had a new starter put on, oil changed, tranny oil & filter changed) an i was looking at the exhuast. when i press up on the exhuast near the cat converter i can see where there is like a gasket bad by where it connects to the header. ( this is where im gettin the smell from an i believe this is why im gettin a catalist inefficentcey code.) umm as for the exact code i coulndt tell you bc it was checked with one those walmart special code readers an i was watching the guy when they checked it an all that it said was catalist inefficencey so.. there is something strange about this neon though i have driven many neons as i use to work at a dodge dealership an i have come to the conclusion that either an old women owned this car or they put a new engine an tranny into it bc it has almost 142k miles on it an it drives like it isnt even broken in. an for an auto this car accelerates really fast for being bone stock.!