black smoke.... help
 

ive been told by my freinds that i blow black smoke when i get on it. what could be causeing this? i never noticed it and ive look in my mirror to try to see it but cant, i ran some fuel injector cleaner and ive only burnt half the tank off so i dont know if its been cleaned yet, but what else could be causing this problem? i think its carbon build up but from where? anyone know?

Black smoke is unburnt gasoline and means it is running too rich. 99% of the time it is the result of a bad oxygen sensor or sensors.

How many miles do you have on your ride? Generally speaking, O2 sensors need to be replaced every 50,000 miles. Supposedly, OEM Honda sensors will last 65,000 miles, but I don't believe it...

thanx man, i have 109k on it and am not sure when the o2 sensors were replaced if they were, where are they located on a 94 h22 prelude? i dont see one on the intake, should i buy the honda ones or are there aftermarket ones that could be better? the o2 sensors are electronic correct?