Ok for a couple of weeks now my check engine light has been going on and off, and I have not had a chance to get the code read. But, even with the check engine light off I get sometimes what sounds like a "dieseling" noise when I accelerate. Is this an exhaust leak or is it pinging? I only have 38,000 miles on my '02 and I already changed the plugs (preventative) and have used synthetic oil (Mobil 1) since my first oil change. I just put some Lucas Fuel System Cleaner stuff to see if that helps, but does anyone know what it might be or what might be causing it? I hear it mostly when I accelerate lightly. And I think that it does it more when I've been driving in stop and go traffic more, or I just hear it more then. Just imagine a diesling sound but more metallic sounding. Thanks.