So I torn into my 04 droptop with 50K on the clock and I am getting some DTC codes. I added XS headers and xpipe no cats, into my Borla stingers. Also added SLP blackwing intake, E3 spark plugs, MSD 8.5 wires, and deleted the air system on the car.

I have HP tuners and tuned out the rear o2 sensors as well as the air system.

So the codes I am getting is P0131, P0141, P0151, and P0161. I got the codes about 20 mins after running the car around on the stock o2 senors. I replaced to o2 sensors thinking the old ones might have caused the issue, but the codes are still showing. I have checked the wires making sure I didnt twist or crimp anything. Checked for exhaust leaks and I am good there. I am about to street tune with all the new parts being on, but I am at a loss as to why these codes are showing up.

Ideas and input from you guys would be helpful. Please if you guys think of anything I am forgetting please dont be afraid to point it out.

 

P0141 and P0161 are for the REAR 02's You need to set these to "not reported and no mil " in your tune----Also set the CAT to read "NO" in the COT system
Furthermore you can also disable in the engine diagnostics section any of the catalyst
reporting
Now P0131 and P0151 are for your front 02's The fronts 02's control the fuel during P/T-----Reason you are getting these is because of your long tube headers --With LT's the 02 bungs are moved further back than the stock location-sometimes as much as 3 ft
This causes your 02's to not heat up properly and not read correctly----This is why they are illegal in many states----
There is no 100% iron clad fix for this but here are a few things you can do that have worked in some cars
1. Install the REAR 02's onto the front location----The rear 02's are far more sensitive and seem to heat up better
2. Lower your 02's switching points or rich/lean thresholds--Start by taking out 100 millivolts to the entire table / tables---
LT's make your P/T fuel RICH lowering the switching points should trick the ECM into leaning it down-----
You can data log your 02 voltages---Read what they are before this change and then again after----The number needs to get lower But you need to run it awhile to get a good average-------Only a wideband can verify your actual AFR which should be 14.68

 

Thanks tblu92! Damn this was helpful!