I have a 98 civic ex, all stock except an AEM cold air intake and a MSD ignition system, where the MSD box is mounted on the firewall and the coil is mounted on the shock tower.

Problem is, whenever it starts to rain or on a really really humid day, my car will crank but will not fire, but when the rain stops and the roads dry up, the car starts and at first it will run rough but then idol fine. Also if i know its gonna rain, i ll start the car, let it warm up, and when it does rain, as long as i dont let the car cool off, the car will start fine while its raining. What the hell could the problem be. Grounds? MSD ignition?

Any suggestions?

 

moisture related computer problem. make sure all your connections are good, your distributor cap is seated properly and not letting in moisture, and that your msd boxes arent falling apart or cracked somewhere.