Quote Originally Posted by poid View Post
the tune on a stock car and a good aftermarket tune are two very different things. If you've ever seen a stock datalog you'd know just how stupidly rich the stock tune can be. That is because its a generic tune for a variety of drivers, fuel quality and engines (stock engines will vary from the factory)

A good tune wont be so rich that you blow black smoke. Especially on an NA street car, they simply dont need to be run that rich. Even for 'safety'.

BTW the suggestion about checking the PCV is also a good one.
I reckon he should get his car retuned, with a dyno test before so we can find out the A/F ratio.