Issue 1 has been here for the long run. I've been thru 2 different o2 sensors and 2 zzp extensions since I installed my SD headers last year. These codes will not go away and it's affecting my gas mileage. P0035, p0036, p0141 and I think a code p0135 Idk I'd have to check again. It's all involving the front o2 and Idk why. Something said low voltage bank 1 blah blah. Anyone had this issue or could give me a possibility? Issue 2 is a random misfire code. Upon startup car idles pretty rough and after awhile it evens out. The misfire does not affect drive ability at all only idling unless I have the ac on. Plugs are fresh,coils done just over a year ago but I'm thinking maybe my wires? Injectors are firing and compression is good. Any ideas?