I had a y7 head and intake manifold and swaped it with a y8 head and intake manifold vtec and p2p ecu but it is blowing codes for oxygen sensor and knock sensor and this guy says if i get the ex wiring harness then it should have anymore codes and also it has a hesitation...i have the y7 headers and o2 sensor on it could that be the problem or is he right about needing to get the wiring harness

 

No he is not correct. You shouldn't be getting codes for the O2 sensor unless one of them is missing (is the code for the primary or secondary O2?) or you broke one of them. In cars with a factory Y7 motor the harness has both O2 plugs in it, in stock VTEC 96-00 Civics the secondary O2 hooks into a jumper off the dash harness. If you swap out your Y7 harness you won't have any place to plug in the secondary O2. The car will run OK w/o it but you'll always have that code unless you strip the secondary O2 wiring from the Y7 harness and add it into the Y8 harness.

Simply changing harness won't make the knock code go away, you have to actually install a knock sensor to plug the harness into.

Have you got VTEC up and running, and is your IACV working already?

 

vtec works but their is also a code for the iac valve...so what r u saying i need to do..cuz i want fix this hesitation problem i have and also to to clear codes to pass inspection

 

Did you perform the 2-wire IACV conversion when you put the manifold on? That will clear that code and fix hesitation and jerking.