I have a 99 Max SE Limited Edition. A few weeks ago I noticed a knocking sound in the engine. I asked around and was told that my fuel injectors might be clogged. So i bought the fuel injector cleaner and on the bottle it said it was supposed to help engine knocking. Well after I used that it was fine. By the way I use regular Mobil oil.. But a few days ago it started again. This happens when im waiting at a light or when im just stopped. Its definately a knocking sound and I can feel the vibration from the car when it knocks. I was wondering what I can do? I am bringing the car to the dealer next week. I would like to know if anyone has had the same problem or knows what it could possibly be. Thanks i would appreciate any help.