Having a sudden problem with my '87 2.6l with a Weber conversion.

A couple of mornings ago it suddenly started up rough ÔÇö sounds like it's misfiring on one cylinder, but it comes and goes. As it warms will idle fine one minute, then the next it will start missing. Sometimes it misses at idle but clears up when the throttle is increased, sometimes the opposite. It was perfectly fine the day before.

As part of my troubleshooting, I found one of the spark plug wires had slipped out of its holder and was resting on the belt tension adjuster. It had worn to the point that you can see scorch marks on the adjuster frame where the wire was clearly shorting. I thought that HAD to be the problem, so I replaced the wires, cap & rotor. Also, the timing appears good (hasn't changed). The problem persists.

I've never encountered a bad coil, so I don't know whether these symptoms match a failing coil.

Any other ideas are welcome.