To be honest Ford Probe catalytic convertors don't get blocked very often. To check if yours is blocked start your car from cold, and get someone to press down on the accelerator while you check the tailpipe, if there is no blockage you should see a steady flow of white exhaust fumes.
If it partly blocked there will only be a small amount of fumes, because the blockage will create back pressure in the system.
If it is blocked, a good way to clean it out, (especially on diesels) is to get the engine warm and then rev it hard. From low to high revs, as far as it will go. This will also generally clean anything bad from the system!
If this doesn't clear it, a visit to a mechanic may be in order unfortunately!