Engine Mechanical problem
2001 Other Saturn Models 4 cyl Two Wheel Drive Manual 78,500 miles

I have a 1.9 SOHC engine in my Saturn. It runs pretty well but I am hearing a noise. Under moderate to heavy acceleration, under 3,000 RPM's I hear a truck dieseling sound coming from the motor. As the car reaches a higher RPM it disappears and sounds normal. Seems to be worse going up hills or generally under a high load situation. I have new plugs, air filter, PCV, and have used Lucas fuel injector cleaner and Seafoamed the engine. I'm averaging 34-36MPG city consistantly. I need to know if this is pre-detonation issue and if I am causing engine damage. Saturn said it could be the EGR but I didn't want to just replace it for 150.00 to "see if it works". Let me know what you think.

Thanks,

Mike