Toyota Repair: Rough Idle, bosch spark plugs, nippon denso

Question
I drive a 1991 Toyata pick-up extended cab (2.2 liter).  I changed my spark plugs last year and put in Bosch Platinums.  I noticed later in the manual that I should have used NGK or Nippon Denso plugs.  I changed the plugs again this weekend to NGKs but the engine is still running very rough in idle (kind of like a "cough" occasionally instead of smooth idle).  Could the Bosch Platinums have done any damage?  Could the torque on the plugs have an affect?  What should the torque be?  Any other idea why it might have a rough idle?

Answer
Try replacing the spark plug wires, distributor cap and the rotor. It appears that there is an electrical misfire, if that doesn't solve the problem have the engine compression checked. The bosch spark plugs have nothing to do with the problem and neither does the torque.