Got a bit of a problem here.... fitted a Librands sports cat and manifold to our 2015 Plus 4 a few weeks ago, runs great when warm but cold start is an issue. Checked fault code and got P0135, i.e. heater circuit in oxygen sensor faulty. Is this normal after fitting the sports cat, and what can we do about it? Trying a change of plug to iridium (but that's another issue).
