this question really had me thinking so I went looking through my manuals and in the troubleshooting part they had a symptom that sounded like your---"Pining or knocking engine sounds during acceleration or uphill" If you think that is iy the book recomends you check-- ignition timing,grade of fuel, fuel injection sysem, spark plugs, dizzy components,faulty emission system, vacuum leak and carbon buildup in cylinders. I know it sounds like a lot but it is a lot of basic stuff you can check and go over...hope this helps!