Having a problem with a cylinder 4 misfire issue. This happens when the car is under load mostly, and feels almost like the engine is lugging at too high a gear. The odd thing is that there is a chirping sound that happens at the same time.

I would guess that it is a coil or spark plug wire issue, but the odd sound makes me think it may be something different.

The Civic is a five speed with 250,000. When the engine does not misfire and is at idle, it runs smoothly.

Ideas? Thanks.