hawkman74

Howdy,
I am working on an 05 civic ex that has a bad misfire. It will barely idle and the misfire seems rhythmic and doesn't go away at higher rpms.

We have tried:

• new spark plugs (old ones were only a few months old but were dry and dark from rich I assume so wanted to rule them out)
• checked compression (all had around 210 psi)
• cleaned the throttle body and IACV
• Unplugged EGR
• Checked for vacuum leaks, couldn't find any. at Idle the map sensor is only reading about 8psi of vacuum (via obd live data) but with revving it got up to about 21 psi

Here is the WEIRD PART: I tried unplugging the coil packs one at a time while someone held it at about 2k rpm. for all but one, the engine dropped rpm and sounded worse. BUT ONE when unplugged, causes an increase in rpm and the engine sounded about as good as it can on three cylinders.
I tried swapping the coil pack with another cylinder and the behavior remained on the same cylinder.

So if it is cylinder-specific, and not compression, plugs or coil, should that only leave the injector as the problem? Upon visual inspection, The plastic part on the end of the injector surrounding the nozzle has a bit broken off. I was thinking maybe it is causing the o-ring to not seal.

Any ideas for what else I should check for?

I have a few days while I wait for the new injector. Thank you!