Pull out filter and look for leaves and other debris in filter slot.
Honestly, I've never read the TSB.
2009 v6 vert. My first mod - Sequential Taillights Kit! Ha ha.
Other minor items, X3/XF3 Tuner w/custom tune, GT Dual Exhaust Take-offs, FR 8.8” 3.73 limited slip, JLT Oil Separator, rear sway bar, strut tower brace.
Innovate WiFi, OT-2 ODBII interface, and DashCommand software to go with it.