Hi, I recently acquired my first Honda and looking at the fuel trim im pretty sure I have an air leak, so I sprayed carb cleaner at the EGR valve and bingo, Short term trim took a nose dive.
Bought a new gasket and installed... still getting nearly 10% stft at idle.
Did carb cleaner test again with same results.
Removed EGR and found the air is being sucked in from the upper part of the shaft (not the valve sealing surface).
Bought another used EGR valve and that leaks in the same way.

So.. is this normal for Honda EGR Valves to leak a little air into the manifold?
2004 Civic 1.6 i-vetec executive, petrol auto

 

I don't Know, but I'm here to learn.

If it's leaking around the gasket, you might need to have that part of the head or EGR cleaned/machined