I just recently installed speed daddy headers in my 04 mc s/c...took me 14 hrs to do and even still im trying to get it to run perfectly lol my check engine light came on obviously but the weird thing is that before my headers i was pushing close to 8 pounds of boost. Now im only pushing 5. Any idea as of why that is?? Another thing i noticed today my car was on empty so i went to fill up and it automatically stopped pumping 3 quarters of the way done? Could that possibly have anything to do with my o2 sensors at all? Idk why my car is acting weird like this?