Hey Scer's first of all my car runs great. It's a daily driver new rebuilt engine installed by myself.However at hard accel WOT my co workers notice as I peel out of the parking lot after work. Black smoke comes out of the exhaust.The car idles fine,And I just got a smog test all good --but NOX too high.Sound familiar, my car has no egr valve.But thats another story. By the way ther is no C.E.L. associated with this problem.All sensors are all original equipment.91 sc man trans blk on blk.