Running rich ? or at least smells like it.
 

mmm okay i replaced my 02 sensor about a week ago and the car is running rich.( before i replaced the 02 sensor it ran great. didn't have that smell. ) NOW i can smell it from the outside from the exhuast.. even on the inside when im driving on the freeway surely there i suspect an exhaust leak. and the gas mileage has dropped. so what could be wrong?
timing ?
tps ?
spark plugs?
oil change ? ( i have bout another 250 miles to go until i reach 2500miles ) i going to change it then.
I have noticed it is a bit hesitate or not as smooth. as it was before i replaced the 02 sensor.
so what ya'll think is the problem ? thank you for the help