I have a 2008 grand prix that makes a constant ticking noise. It has approximately 200,000 miles on it. Mostly highway miles. It sounds like a lifter tick but never did it until I had the timing chain and water pump replaced. It also seems sluggish at times. I have a 2005 grand am also which makes the lifter noise but not constantly. So it makes me think it's something more serious. It's also leaking oil. If anyone has any suggestions I'd appreciate it. 😁