Just installed a Tremec T56 magnum XL and ARH long tube headers with high flow cats. I originally had 2 rear O2 sensor codes which I expected and a misfire code for cylinder 4. I returned my steeda tune back to stock and took it to a shop with have the whole crank sensor relearned. After I got it back I reinstalled steeda tune....this hasnt been updated to go with all my new mods, but wanted to drive the car a little before I get it dyno'd. No problems for about 30 miles and then I started getting misfires allover the place. Cylinder 4, 7, 3. Just curious if you guys have any suggestions. Im hoping the tune is the issue, but concerned it might be something else. I did use 1 O2 sensor extension for rear passenger side because my harness would not reach my headers, but considering removing that and soldering wire in to make my own extension. Love the new feel, but now concerned that Im not going to be able to keep the car running without a check engine light on. Any suggestions are welcome? Thanks.