I've seen a few posts about this before...people claim its from rich exaust, ie to much fuel, like at startup until it warms up. Not true!
Get yourself a catch can, then clean the tips up, amazingly it won't reappear...it's from the oil that get's sucked back into the intake and burnt in the combustion chamber. Look at almost any newer car and 90% of the tips have that. My wife's 2013 Kia Optima is horrible...
SLP Loudmouth 1, Y pipe, resonator delete, 5" Tips, Belltech 2/4 drop, 305/50R20 Nitto 420's, color matched interior, Upper Glovebox, Sport seat covers, Leather Steering Wheel, Dball, BBK Headers, Edge 2800 Stall, V6 fan swap, ported TB, Vararam, 180* tstat, Hemifever tuned, custom 392 Half Covers