Good evening! I'm new to this forum and I've always found them very helpful, thank you all for your input!

So I have a 2001 Honda prelude with a H22A engine swap and a manual trans swap. I've been driving the car for a bit with a knock sensor code and P0138 issue. I resolved the issues. I'm not sure if that matters but I wanted to provide some background. The problem I am having now and have had 3 times prior, is a bouncy tac and it sputters occasionally (loudly). I've pulled codes and the only code I am getting is the P0138 code o2 sensor. I replaced the ICM 3 times to fix the bouncy tac and it seems to work for a short while then goes back to the way it was acting. Another thing that I noticed when I was doing the tranny swap, replacing the oil pan gasket and pulled the exhaust down pipe, there was a significant amount of soot. I'm wandering if all the problems are associated with back pressure? My daughter claimed she heard a loins bang that came from the back of the car... Any ideas would be a great help!