You most likely have a secondary side ignition component breaking down causing the initial miss fire then, the ECM is shutting down that particular cylinder to prevent the cat from overheating. A oxygen sensor does not usually cause high roughness and won't cause a specific cylinder to drop out.

I know for sure that the 97 ME - SFI system does this, not sure if the 96 has HFM - SFI this level of control or not.

Run the scan tool and look at miss fire counts, if you see a cylinder with high counts, move that coil / wire / plug to another cylinder and see if the problem follows.

It seems that the coil on plug side of the coil fails more often than the wire side. ( One coil runs 2 plugs.)