My car had already done 27k miles when I purchased, so I figured that I needed to do Something sooner rather than later. Read lots of stuff about the GDI issue in general but didn't find anything specific for the Ford/Mazda engine, I also remember reading something about how a non-turbo GDI may be less affected.
I considered for some time, removing the Intake manifold as it would enable me to a) find the bottom PCV connection with a view to fitting an Oil catch can and b) to inspect the back of the intake valves and determine how bad they were fouling.
Did some research on how to remove the Intake manifold, but without a Haynes manual I didn't know things like torque settings for the bolts or if any gaskets would need replacing when putting it back together, so I decided it was a bit beyond me and didn't bother!.
In the end I just treated with CRC GDI Valve Cleaner and I'll repeat at regular intervals.
