We have a 2011 Impala 3.5 that has always run good never an issue it has190K, this past weekend we took a 100 Mi. trip out on the highway average speed 70 good ride no issues until the next day I can hear some light intermittent valve lifter ticking that it didn't seem to do before as it warms up the ticking gets louder then when it's hot the ticking sounds more like chirping it's not 100% continuous stops now and then for a cycle or two it does run and drive fine. I checked the oil and learned my wife added oil a couple of weeks ago and it was over full by one quart I have run Amsoil in Chevy since 39K MI. I did change the oil and exactly the same. I disconnected each spark plug one at a time and connected a dummy plug for the spark to continue the sound didn't change the bottom does seem tight no crank noises, I believe this 3.5 might have a bad lifter it's the chirping sound that's strange anyone have this happen?