My downpipe has cracked before the 02 sensor, could this be why I am getting a code 16 (Fuel Injectors) and code 43 (Fuel supply system)? Could it be because not enough exhaust is hitting the 02 sensor. I have a Drag down pipe. I am going to see if the exhaust shop can put a flex-pipe right at the bend where it starts to straighten out for underneath the car. I already have a flex-pipe near the o2. When you put your hand over the crack, there is a considerable amount of exhaust that escapes!!