S3 light is just for the trans just means there is a signal problem that's making it think its not in over drive if it is shifting smoothly and going in 4th then your fine. Check ur spark if spark is there spray Carb cleaner in intake and see if it fry's to start if so you will have a fuel probablem. Which is usually the fuel pump but I did that on a stealth and replaced pump and found out that the injectors were not opening which is crank sensor on that car
