[detltu]

This was the main consideration that kept me from installing a catch can. Everyone has said CAI and catch can are two of the first mods you should make. I am leaving mine completely stock until the warranty runs out. The warranty is important.

If the car is fairly new and the dealership really did flag the car that is a dick move by the dealership IMO. Do the customer a service and warn him that if he doesn't return the car to stock he will risk voiding his warranty. Give him a chance before you screw him.

I agree with what others have posted. The issue could be related to the catch can and the dealership can't be responsible for diagnosing problems with aftermarket parts. In this case it sounds like the problem predated the catch can install but I have seen other people with catch cans who had similar problems.