had car dyno tune today, and car is running rich at 4 grand and above on wot, guy could not figured it out either, i have slp 85 maf, and ls6 intake and loudmouth exhaust and slp cold air kit before car ran fine, then i put mac headers with their high flow cats and y-pipe and it started smoking, dyno tuned it with all these mods, guy spent 3 hours on it and couldn't find the problem can anybody help me with this, i have replaced the o2 sensors also so its not that, car is running good feels strong as ever, just like to get this problem solved

 

your aftermarket MAF could be causing your change in A/F ratio.

You need to have your PCM tuned. I make over 400 RWHP on a stock MAF. Aftermarket MAFs are a waste of money IMO.

as far as the smoking, if you had CATS on your car before the headers then you wouldnt see any smoke. After taking the CATS off nothing burns off the excess fuel. this may be the smoking you see.

 

i did have it tuned the guy could not lean it out though, and i still have cats, so people have told me about this maft, would that fix it