Hi,

I got a 2000 Civic DX, 40k. I get a strange metallic ticking/popping sound
usually during half throttle when accelerating through 40-60 mph. It doesn't
happen when I floor it. It disappears when I reach cruising speed. It only
happens when my engine is fully warmed up after having driven 5-10 miles. It
doesn't happen when I rev the engine in park.

I took it to a couple mechanics...they can't hear it, but they think it's
probably misfiring (I thought my car had a knock sensor), and I need a
tuneup. I was also told it might be an exhaust leak or my valves should be
adjusted.

Any thoughts?