Hopefully someone has an idea on my problem: I have a 2006 Trailblazer LS with the 4.2L I6 Engine with 67,000 miles. I have a "whining" noise coming from the engine. It raises in pitch when I accelerate and never stops the entire time the engine is running. I have removed the belt completely and run the engine briefly, and the noise is still there. Upon using a cheap mechanics stethascope, the noise sounds like it is coming from the top front of the engine, inside the area where the oil filler cap is located, maybe around the cams? I have replaced both the tension idler pulley and the idler pulley with no success. Thoughts or suggestions...I have to fix this thing myself and I have never worked on this thing other than oil changes and simple maintenance (idler pulleys mostly). Thanks for ANY help anyone can give.