when in park or neutral, when I rev to 3k rpm engine starts to lope, miss. seems to run fine in drive, I floored up to 5k rpm. Don't know what to try first. Found this while cleaning throttle body, but it could have been doing it since I bought the car, because it only does it in park at 3k rpm. I do hear a click before it starts to surge up and down.

 

2006 , 3.5liter