I have a 1996 Sonoma with a 2.2 4 cyl 5 speed in it. The belt tensioner chatters every time I put the engine under a load. If I lug it down a bit then step on the gas or just shift gears then give it a little gas, it makes the tentioner jump up and down 1/4 to 1/2 inch very fast. It tore up one tentioner already. I replaced it with a new one from GM, which is a Gates. It has a brand new Goodyear belt on it. All the bolts are tight. It still does it. Has anyone else ever run into this, or know what would fix it????????? THANKS !!!