I have a 2003 Nissan 350Z Performance model, it has header, cat delete, H-pipe, resonated. I have had this car for 3 years and all the exhaust work was done prior to me getting it. I am getting the following codes: P0031, P0037, P0051, P0057. and it keeps blowing the 15A fuse. what is could the issue be? should I just replace all 4 sensors and go from there?

 

You could try replacing all of the o2 sensors and go from there although I'd be inclined to get it looked at professionally as this may save you a whole load of ballache down the road.

 

The codes are not that much to worry about as I have all of them on my car or had now I have only two. Your sensors are detecting emission problems because of your headers and test pipes. On your test pipes you need o2 sensor extenders to bring the sensor away from the pipe and that will fix 2 out of 4. Unless they are already burnt and fouled (high probability). The headers sensors will need the same thing...unless they are not installed at all as you do not need them per say because the car would run open loop...or closed loop....forgot which one. I don't have my sensors in my headers as I am on a custom tune. You could always get an up rev tune which I think they can delete the engine light and give you more hp. As far as the fuse is concerned....that might be a fuel pump issue. The previous owner might have installed a high flow unit. 15a is the fuel pump fuse I think.

 

I understand all that but I have driven this car for about 3 years and the set up hasnt changed, and now 3 years later I am getting the codes. I have made the extenders for the rear sensors but have not installed them yet. Im not sure what the 15a fuse is for but it blows as soon as the CEL comes on. and after I change the fuse and clear the codes it will take a few days for it blow again and the CEL to come back on. I dont just want to delete the CEL, I would rather figure out what the problem is and repair it properly.

NOTE: I do have all 4 sensor in.