Hi bernie,
First thing you need to check is battery and alternator. When it is raining we have our wipers,lights,defrosters,radios,ect on. This puts a big load on the charging system. If the battery is bad it may be ok when all these loads are not on , but when they are it may pull the voltage down too far for the computer. Another thing you can check is get a spray bottle of water and spray all over your coils, wires, plugs to check for spark arcing. After you spray snap the throttle and watch for a hesitation or miss. If it hesitates or misses you will need a tune up of the affected parts
ASE Certified Technician
Master ase technician, Maryland state inspector
I drove the car here this morning as it is a rainy day today. The car is driven by my wife and I had not experienced the car in rain or high humidity. The car hesitated and would not shift for the rpm would not go over 3000, so I shifted over to manual and was able to drive. It still would not go over 3000 rpm but I was able to manually shift and it would drop the rpm in the next higher gear and accelerate. It feels like as if a governor was set at 3000 rpm. Again that takes only place on rainy or humid days. In the start up of the acceleration there is a slight hesitation but that can be overcome by accelerating slowly and it will not accelerate above 3000 rpm. It appears that in order to shift in the next higher gear in the automatic mode it has to be over 3000 rpm. It almost feels like a sensor is somewhere not functioning right?