How can you tell if there a problems with the lifters: sound, performance problems? My car has been running great but there is a sound coming from the driver side bank that sounds like an exhaust leak, but when im sitting at a stop light the car idles very awkwardly.

http://www.youtube.com/watch?v=8nzCsil8M9Y
http://www.youtube.com/watch?v=XJzCG1ZEeig