Engine light reduced power engine

The best thing to do when there are issues with a car is to go to a dealership and ask to see the, "Service Bulletins". They do not have to tell the publioc about these but they are still problems that affect cars and they are meant to help mechanics. However you have every right to see if there are any that could apply to your loss of power and the service department has to show you them. Since you have complained you have a legitimate reason to get it fixed at no more cost to you if it has a bulletin pertaining to your issue. Otherwise and even if there is a bulletin I would call GM and complain as much as possible and that will eventually get you some help too.

Dealerships genrally have them but nowadays service manuals are on CD for a computer and it will update the manual if there are mistakes in it and include things like service bulletins. It is worth asking if it is a private shop. But, dealerships have them for sure and you can still take your documentation from private repair and call GM to try to get some, "Good Will Help" they call it.

Okay sounds good.