There is a recall on the Bremrie (spelling) COP's. They are to be replace by the Bosch COP's if found to be faulty. I don't have the recall number handy..
Are you sure it is a COP? A worn sparkplug can do this also.
Most likely it is a COP. It the DME throwing any codes?
There could be a internal code stored in the computer. It will tell you exactly which cylinder is misfiring.