I just put a d16y8 intake manifold and throttle body on a d16y7. I'm fairly certain I got the iacv wires right, converted from 3 prong to 2 prong plug. It idles fine below 1600 rpms, but between 1600 and 2000 it runs lean, the fuel pressure shots to about 45 psi, and the engine acts like it wants to stall. Is this just a vac leak, or do I have bigger problems?

 

If you want to check for a vacuum leak then do this: First remove the intake tubing or whatever you are using. Second start the car and let idle for a few seconds. lastly...Put hand over entire throttle body port. If the car stalls then you have no vacuum leaks, but if the car continues to run while the port is covered then I would check for a leak.

Any surging in idle?
Any fuel leaks?
O2 hooked up?
Also did you use a new IM gasket?
Proper seal?

 

Idle surges a little, there are no fuel leaks that I have seen, I didn't touch any of the o2 sensors so I assume they are ok, and I used all new gaskets. I assume the intake manifold gasket has a good seal because there is no coolant leaking.

 

what ecu are you running?

 

are u running a wide band?
are u reading your plugs?
how do u know ur running lean?

 

running lean according to air/fuel ratio guage
running stock obd2 ecu(97civic dx,d16y7)

just checked the vac and there is no leak
checked voltage at the iacv plug-12.5v

 

you sure you using the right y8 IM .....? what year Y8.. There is one that you have to plug holes in to make it work.

 

You only have to plug the holes if you are using the old y7 throttle body or I think the automatics come with the iacv on the throttle body, but I'm not sure

 

Your AFR gauge is not accurate. its just there for a nice little light show. you need a wideband to accurately measure your AFR