Need help, Service Engine will not go off
Since you've posted in the LS2 forum, one might conclude that your vehicle has an LS2. If so, you're under warranty - take it in and have the dealer figure it out.
If you've erroneously posted in this forum and you have another form of LS1 then go to your local Autozone or Napa and have them pull the code for you. Alternatively you could purchase an OBD-II compatible scan tool (Actron makes a cheap one) and pull the code yourself. Even if the light is off it should be stored in history for a number of drive cycles.
If your vehicle is pre-1996, you'll need to find an OBD-I scanner or use a jumper.
This is the only way to tell what exactly the car is trying to tell you. Once you find the code, post it here or in an appropriate forum and we'll try and help.

