Get a can of BG44k and put it in your fuel. We do them every service . I did it on my own car before I pulled my head , after 2 tank fulls I pulled the head to do a valve job . It was unreal how much it cleaned the piston and valve area.We did look in the chamber with my boroscope before hand and it was pretty carboned up.This is the best stuff I have ever seen . It works best if you put it in before a long highway trip.
