I have a d16y7 that has been making a ticking or tapping sound for a couple months. I assumed it was related to the valve lash so I adjusted the valves tonight but it made no difference. I tried pulling spark plug wires one at a time to isolate a specific cylinder knocking but it is there with any cylinder unplugged. If its a bad rod bearing shouldn't it stop when the cylinder isn't firing ? What else could it be ?

 

You're going to hear some valve noise even properly adjusted. It should get quieter after the engine warms up. Bearing noise won't.

To disable cylinders, it's better to disconnect the fuel injectors one at a time. The Civic ignition coil is prone to blow out if you let it fire into an open circuit.

 

Starting to think its an exhaust leak. The manifold/cat has a crack starting at the sensor. Is it normal for exhaust leaks to mimic valve noise ?