freind has a 98 silverado with a 350 vortec and it was blowing black smoke out of the right pipe (dual exhaust) and white out of the left, we gave it a tune up with replacing the plugs and wire cap and rotor the plugs on the left bank were all carboned up, it had ngk plugs from the last guy who gave it a tune up and we put ac delcos back in it and it smoothed out and theres no more white smoke but the right bank is blowing out black smoke still, we put injector cleaner in it a few times and it still does it, could the catalyc convertor be clogged for the passenger side??? there is one cat for each side of the motor. should we just cut off the cats? we think it would run better and deffinately sound better. any info would be good.

 

bad fuel pressure regulator, or bad oxygen sensor. has nothing to do with cats. in fact, removing cats may cause service engine light to come on as the computer reads oxygen sensors after cats.