i upgraded the injectors on my 1999 GMC 7.4 from the factory one to the ls1 injectors. Truck runs good now. but I now have a SES light on. I have a p0172-p0175. Both rich codes. I assume its because I have bigged injectors. I was under the impression from all that I read here that it was a direct swap. Do I need to have a tune to run these without getting a check engine light. Also my mileage went from 12-15 down to 8-11.