Ok I had a tick when I start the car and goes away until warm. I used a little seafoam a couple months ago to quiet it down which it did. But yesterday while driving I feel a slight hesitation, pull over and hear the same tick noise but louder. At first thought Im thinking a thrown rod bearing. Still uncertain but I ordered new ls7 lifters, and went to take out the old ones I noticed the plastic guide was slightly cracked and when removed two or more lifter were off position by half a centimeter im guessing. Will this cause a lifter tick or slap? The lifters also have a little grooves on them. Just wondering if this will indeed cause that to make a contant lifter tick that sounds similar to a knock, if so how damaged is the cam??? Drove it to the nearest driveway soon a I heard it.