Well... my situtation was:
This one day i just washed my EVO and i havent even taken it out yet. Then when i took it out for a ride about 2 miles later i turned right and it almost stalled. then the SERVICE ENGINE SOON light popped up. i was pretty worried (since it was my baby)... so i drove it back home and left it there for the day. I came back home hoping that the light had gone away but it didnt. Then my dad came home and he turn it on and the light was gone. should i be worried? I was thinking maybe water got into my vents and maybe did something in there.. what do u guys think??

 

i wash my car all the time, water rains in the vents, pours in the vents, all, My car is not garage kept, not under anything, wide open atmosphere, i would maybe get that checked out??

 

code should still be saved in the memory as long as you don't siconnect the battery. should find out what that is and maybe then we can help you further.