i have a problem with my girlfriends car...she has a 2002 z28 and i think it is either a lifter tap or a rocker arm is loose. are the rocker arms on the ls1 self aligning or not and are there any valvetrain problems that usually occur with these cars that i should know about. it is just a slight knock in the engine compartment at idle with not many other symptoms. she says the car is driving differently but we all know that it is hard to tell when it isn't your car.

 

hey;i don't thing rockers can come loose/it could be colapsed lifter hers should sound close to yours minus your upgrades i'm still in third gen but either way you don't want to drive too much until it is fixed to keep from breaking something you/her don't want to have to replace if you don't have to

 

Could be a bent pushrod as they are the weak link in the gen III/IV or a bad lifter. Hope for the PR as you have to pull the heads to get at the lifters.

If it's a heavy knock then maybe a rod bearing has gone south. How many miles on the car and how well does she take care of it?

 

rocker could have puked it's needle bearings as well.