We make all this up.....same as the thousands of techs that have contributed these actual pictures of the issues......takes a ton of time to make all this up and doctor all the photos, and I have only been building race & performance engines and for over 38 years (starting as a GM tech for Pontiac/Olds/GMC in the 70's), and owned/raced/run/mangaged professional drag race teams with years of Divisional, National, and World Championships both NHRA & IHRA.
Click on this link for a compilation of pictures shoing the results of not running a good catchcan on todays DI engines.....this is a group from all makes/manufacturers posted by mechanics and machine shops showing the results. This is NOT just a GM issue....and these deposits we see getting bad at 8-10K miles to the point power & economy is degrading:
http://www.google.com/search?q=intak...w=2021&bih=875