Well my saga continues with my DT long tube headers and y-pipe install on my 06 v8. Here is a series of events, looking for advice on what to try next:

1) Installed DT headers and DT y-pipe last Sunday (5/12) with an experienced mechanic. Removed all the cats. Took 10 hours, no real install issues. Started up the truck afterwards and drove it around the block, no CEL and ran well.

2) Went out later that night and got it up to highway speeds and it threw a CEL for the O2 sensors (P0420 and P0430). Took it home disconnected the battery then drove it around again, CEL came back on for a O2 sensor error. Called Jason Burtman who I bought them from and he said I needed CEL eliminators (basically metal 02 spacers), and he sent me 4 of them.

3) Went to install the spacers yesterday morning using the original O2 sensors, and after I got done, I started it up and got a CEL for code P0057 which is bad downstream O2 sensor.

4) So now I go and order 2 new downstream Denso O2 sensors (part number 2344261) from the local Advance Auto Parts. They came in the morning, and when I went to install them they were longer than the ones that were in there originally, see photo.



Passenger side fit ok on top of the spacer, but the drivers side would not fit without loosening the y-pipe, screwing in the sensor then retightening the y-pipe to the headers. That being said the wires coming out of the 02 sensor were rubbing on the frame with zero gap. Got it all back together and decided to disconnect the battery for 30 mins again just to give it a full reset. Started it back up and it threw 5 codes this time:

P0037 B1-S2 HEATER ISSUES O2
P0057 B2-S2 HEATER ISSUES O2

P0102 MAS AIR FLOW SENSOR

1440& 1443 0AIR INJECTION SYSTEM

Super frustrated at this point, I took the truck out and tried to drive it. It stalled at the first stop sign. Was able to get it back to my house and decided to remove all the spacers and go back to what I started with. Jason suggested I remove the front 2 spacers first , so I tried that, no luck truck shuts off. Removed all the spacers disconnect the battery for another 30 mins and fire it back up and immediately get all 5 codes again but seems to drive ok.

4) Drove it to the shop to buy some MAF cleaner and it seemed to be running ok but still had the CEL.

Note: I am running the Slyfox air injection bypass but didn't get a code on that till today when I added the new 02 sensors.

So now I am stuck and looking for help. I have my mechanic friend coming by on Sunday but Jason suggested I see if anyone else could help troubleshoot. My questions are:

1) What are the chances I get 2 bad O2 sensors out of the box? And why is the new one so much larger? I thought Denso was OEM?

2) Why am I now getting and MAF code? I got some cleaner but haven't pulled it out yet to check it. Going to do that when I have some time tonight.

3) I called Doug Thorley and they said the O2 spacers should keep the CEL off, but weren't much help beyond that. They said if I was getting the air injection code that there was a leak somewhere, so I went and retightened everything but still getting the code.

Looking for any advice on how to move forward besides taking it to a shop, thanks.