Cavalier 2002 4 dr sedan engine repair light on? and problem when starting

OK, I got 2 prob., 1st, when its cold and rainy outside and i start the engine, the motor kinda "wobbles" up and down more than usually.... if u think u know whats wrong tell me

2nd prob.: The repair engine light is on since 3 days, it has 69000 KM on it, and i did a check up on it 3 weeks ago. When i accelarate from zero, it has a little problem changing gears (automatic). And today, (is a rainy and cold day) , i saw that the RPM, when i accelarate, sometimes starts going up and down for a second or 2.:disappoin

First change your ignition wires(wet problem). Then pull your trouble codes and see what the computer does not like.