What size of hose do I need to do the sea foam? cheers

 

Use the PCV hose, no extra hose is needed.

 

The PCV is the hose going from the passenger side valve cover to the intake plenum. Use pliers to restrict the flow so it takes 1-2 minutes for the engine to suck in the whole can. Once it's in the engine turn it off and let it sit for 30 minutes then drive it like you stole it and watch it smoke in the rear view. While you're waiting for the Seafoam to work use an entire can of throttle body cleaner and clean the throttle body. Make sure to open the butterfly valve and spray inside really good.