crap, for the first time ever my engine is ticking and quite abit.at idle when you rev or drive.it was running great this morning but after work started it up and it starts ticking and kinda slugish.checked the oil it was fine and changed last week. i think its the vlaves or rockers ticking.kinda sounds like its coming from the back of the head where the intake manifold bolts to the head. how can i be sure thats what it is? and how would i go about adjusting them?