just for learning, Let say if the LS (manual) ECU isn't working probably. Is it okie to replace an LS (manual) ECU with an LS (auto) Ecu? both are LS though, wonder if they make a difference//

 

The LS auto ecu will run it, but not good. It will run like crap, spit and sputter, I would only use it in an extreme emergency. A friend and I experimented, and found that an LS manual actually will run better with a GSR ecu than with an LS auto ecu.