Hi, I have a bb2 prelude si 5 speed, with a fresh h22a motor swap, with rougly about 40-60k mileage on the engine. My ecu is a p13. I currently keep getting a cel for oxygen sensor "code 1". I have replaced my oxygen sensor with a working Oem one. I still get code 1. I have also traced all the wiring and followed the cars manual, and all of my connections tested out correctly. I am stumped, the car is receiving horrible gas miles, and bucks when letting off the acceleration. It also bogs a-lot. The only part I am missing on my prelude is the IABS, which controls the secondary butterfly's inside my intake manifold. Would this cause an oxygen sensor code? I am considering pulling my ecu and looking for leaking capacitors. Also, sometimes when I start the car, it seems to run perfect. Other times, the car will run like ****(excuse my french), and sometimes it will run in-between. When I say running well; I of course mean, more power, and better throttle response. Thanks for reading, any input on the car would be great, I have been stumped on fixing this code for several months.