Hey guys, I'm pretty new here and I'm looking for some help. I recently installed a set of stainless works headers and a exhaust on my 6.2 (such a pain in the ass) and then got an X4 from 5 star and I've been having some serious issues with the tune. I loaded the maps that they built for the truck and when the truck first starts while it is in closed loop it runs perfect, but when it goes into open loop it starts to studder and idle really rough. Sounds like it has a giant aftermarket cam in it. While monitoring the gauges on the tuner it is not making corrections to the O2 sensors (reads 0.00 or 28.13 AFR). The rough idle will kill itself if it runs long enough. I tried 2 different maps and it does it on both. We looked for any vacuum leaks (none found) and made sure that the O2 sensors was tight and plugged in. I do not think that the O2 sensors are bad. All header bolts/exhaust bolts are tight and there are no exhaust leaks anywhere either. I believe this is a software issue as it runs perfect in closed loop. On closed loop it idles at 700-800 RPM and the AFR is at 15-16 and feels great. I've sent them data logs of whats going on and all they have suggested is changing my O2 sensors because they have seen them go bad after doing this kind of work and I changed all four to no prevail. I also removed the Stainless works O2 sensor extender because we found out that the extender causes problems similar to this sometimes. I've tried running the stock tune on the truck and it does the same issues with it as well. It's getting kind of hard to work with 5 star because I'm getting one email every other day or so with them not answering my questions at all, so I'm wondering if anyone else has had these kinds of issues after installing SW exhaust parts or running tunes from 5 Star? Also, does anyone know of any companies that dyno tune Raptors in the Northwest, just incase it doesn't work out with 5 Star. Anywhere from Portland to Seattle would be fine. Thanks guys!