While on a road trip heard slight ticking then mostly went away, left me with a rough running engine, service engine soon flashing, checked compression all ok except #4 at 25lb, I tested this cyl 10 times twice it pumped to 100 lb. 3.8 supercharged have owned and cared for since it had 58k now has 110k 2001 buick 3.8 supercharged.