So...the swap went very smooth and have to say, im very impressed with the way it runs open loop. The only problem is, it wont go closed loop. I'm getting the O2 failed code. I had installed a heated O2 several monthe ago, but in the header. First, I'm going to double check the O2 pinout. But, I had read where 95 trucks had the O2 mounted further back in the exhaust. I do have a bung in front of my cat. Would that be a better location for the 7427?