SES playing games

HI,

I am new to this forum. I have '99 SL2 and it runs great has around 110k on it. I have been seeing this problem lately. The "service engine soon" light comes on for a while and then vanishes. Then i dont see it for days untill it reappears. I have been ignoring it for now but with winter coming i am not sure if i should be ignoring it. I have observed this one thing though. I see this light only on damp days but not on all damp days, could it be an electrical thing.

Also i wanted to know if i need to wait till this light is on before i take it to get the check done or can i take it any time.

Thanks for all the inputs in advance.

Jf1

I believe the codes are still stored even after the light goes off unless you disconnect the battery or pull the PCM fuse, doing either will erase them and if there is still a problem they will come back. go to autozone and they should read the codes for free. Post them here too.