Well I had had my neon 2 weeks now....... And just recently while driving the car I was having black smoke coming out the back of the car. The engine didnt seem to have a problem driving didnt hesitate at all. Id say the smoke looks blackish grey using my best judgement. It does it on a really light scale when idleing. Took the car to get it worked on and what do you know.... The dang thing didnt do it!!! I was wondering what your all take on it was. I was thinking perhaps since when I got it. They used a bad air filter? Bad spark Plugs maybe?

I have a 131 HP 03 SE Sedan
Manual Tranny

I dont think I was too hard on it. Its under warranty but they wont fix what they dont find. Perhaps the catylic converter? Maybe somthing miniscule since it whent away I hope???? ANy input would be great...

 

There was also a horrible odor like rotten eggs or somthing but that SURELY DID STINK

 

Its your catalytic converter.