ok guys I have a b18a1 swap in my hatch and im getting a big power losse in low rps and a huge misfire when down shifting misfire and idle back fireing but my car starts good and will run but run like crap
help plz if you can heres things I have done

new plugs wires cap and rotor
new dizzy
new fuel pump and filter
new ecu

I have 2 check mtor codes there
15 and 41
15 I cant seem to get a good ex. for
41 I no the o2 is bad
my old accord had a bad o2 and it made the car stumble and sput like crazy not sure if that's is my problem

and have any advice?

 

Yes...replace that o2 unless you'r ECU is chipped and runs constant open loop(with a good fuel map) it could very well be causing what you are describing. then check you'r ign timing 15 i can't find much on either

 

code 15 is ignition output signal the signal going to the icm might have something not plugged in good at the dizzy

 

http://imageshack.us/f/292/code150pw.jpg/

 

also

https://honda-tech.com/forums/honda-crx-ef-civic-1988-1991-3/htf-do-you-fix-code-15-a-1656532/

 

I put a brand new dizzy from Honda on the car still same code

 

are your spark plug wires in the correct order?? 1 3 4 2