smj999smj wrote:I went with the DT shortie headers and mid-pipes, keeping the upstream converters. If you go with no converters, you'll have to get a custom ECM tune from UpRev for two reasons. First, without the upstream converters, the P0420/P0430 catalyst codes will constantly trigger. Second, without the converters, these engines for some reason tend to run too lean, from what I've read. And, "yes," there are bungs for the O2 sensors.
LOL I already have the P0420/P0430 codes all the time. Seems my cats are getting old. Interestingly enough, they don't trip the code while cruising, only on cold start when driving in town or short distances. Once I have my cruise set to 70MPH, I can reset the CEL, and it won't turn back on until I stop the engine, let it cool, and restart it.
I probably won't get out of changing the cats, if we keep the truck for too much longer. And you can't buy used cats from the wreckers here either, illegal to sell them apparently.
What I've heard is I could 'trick out' the ECM by using some spark plug anti-foulers on the secondary O2 sensors. This would pull the sensor out of the exhaust stream enough that they don't trip the P0420/P0430 code.
The other thing is that I've never replaced the O2 sensors. I have replaced the F/A sensors, but that was over 4 years ago. Wonder if the O2 sensors are getting weak, the voltage seems to jump around a fair bit, and I've read that they can become lazy, which would also trip the codes I'm seeing.
Sounds like I need to probably fix/replace the cats.