Have 2000 ZX2 that runs very rough whenever it is raining or wet outside. Never thows a code. changed plugs, wires, ignition module, fuel filter and I see no change. Only happens when there is moisture in the air. Could it be bad M.A.S. ?

 

Something you could try; next time it is wet and acting up , unplug the MAF sensor and see if there is any difference. If the problem goes away , you could be reasonably sure the sensor is defective.