I have recently thrown a code description Heater circuit insufficient flow or something. When I had my tune, I turned off the rear O2 sensors due to my longtube headers. It is running a little rougher now and it seems I have lost some low end power. I have changed my setup a little so maybe I need another tune, but what can I do about this code????

 

that code means that your 02 sensors are not getting warm enough to help with cold engine emissions. nothing will be hurt by it. just annoying to have the light on your dash. will not effect performance.

 

I ran my car with that code for a long time. One week it did get bad. I replaced the front 02s with rear vette sensors and have not had a problem or engine light since. My driver side sensor was so bad I replaced all the plugs as well because that bank was so rich.