I recntly bought a 93 civic hatch with a 2000 Civic si b16a2. I run a p30 and I am guesing who ever did the swap got it runing and that was enough. I took 6 trips but I finally passed emiisions I had to wire a 4 wire o2 sensor If only I knew then what I knew now. But now after wirining the 02 and an air intake temp sensor I still get a check engine light. But no untill the engine is warmed up. It is code # 23 which is Knock sensor? Did the b16a2 have a knock sensor? Or should I just run a p30 I dont mind runing with check engine but also it makes the idle jump fron 750 to 1250. Can anyone help????