Okay so, I was on my way to lunch today in my 92 YJ (stock 4cyl) when I noticed a strange sound in sync with my revs. It sounded like a supercharger. I called my wife to see if she installed one while I was sleeping....well...she didn't...:banghead:. So I happened to stop by a 4x4/auto mechanic shop where a very nice mechanic used a crudely designed stethoscope to listen to different parts of my motor. The noise could be heard in neutral or in gear. So he listened to my alternator first with my rpm at about 3500. Then the idler pulley. He walked away and grabbed some spray and spray the *** out of my idler pulley and the sound went away. Nice, I hate not being able to diagnose a noise. Just had to do this with my U-joints (Diagnose noise). Anyway. So if you here something that sounds like a turbo, and your wife doesn't work under the hood nor is it Christmas....just check your idler pulley. Now...How to replace this thing? Is it pretty simple? Any tips?Thanks!!!