I have my 818 nearly complete but the check engine light stays on. Pulling a code shows the PO447 which is a generic emission code for the recirculation of gas vapors. I have checked all the rubber lines, the electric connections, etc,. and the previous builder installed a new charcoal cannister and can't find whay causes the code. If I delete the code it comes right back. A mechanic friend questioned whether the tank is properly vented and the gas cap sealed. It is the FFR supplied tank and the gas cap fits tight. Any suggestions where to go next? Additionally the prior builder installed an aftermarket turbo and wastegate and as a result I'd like to get a local tuner (Massachusetts) to take a look at the setup.