Undiagnosable misfire 2005 Honda CR V

[Katie]

My mom’s car has been misfiring on one cylinder for a while now. Full disclosure, it started after the main seal went bad and instead of repairing it immediately, we just kept dumping oil into the motor. There no sign that oil got into the cylinder. After replacing the seal we changed the crank shaft sensor out, got a new coil, replaced the plug and still misfiring. There’s spark apparently as tested by a couple different people, one an actual mechanic. I did find this tutorial on YouTube however where this guy determined that the CR V he was working on had a bad ground. The wiring to each coil is run on kinda like a circuit, I wanna say, maybe?!? I’m not sure how to describe it exactly. Here’s the link to the YouTube video: https://youtu.be/PMNOyGiwoAA. Sorry if that’s not allowed, I’ll check and remove later if it isn’t. Anyhow, what I’m curious about is if the plug could still be getting spark with a bad ground? The way I figure is that spark would theoretically indicate there’s a connection with the ground but that doesn’t necessarily mean the ground is making a strong enough connection to fire the cylinder. I’ve seen similar instances. I tried getting the last guy that was working on it for her to just run a jump wire to appease my curiosity and I’m not really comfortable doing so myself but he just kept insisting there was spark so it couldn’t be the issue. He sent my mom back with a read out of the codes her car is putting out but I’ve not seen it as we both keep forgetting about em when we cross paths. I’m sure my mom has misplaced them by now.

If anyone has any knowledge, advice, suggestions, or even to say that I might be right, I’d be super grateful. A bad O2 sensor wouldn’t cause a misfire would it? I forgot we put off replacing it as it’s a $200 part and I just think that’s an absurd amount for one sensor. I thought that I should add that as well. Oh, and about the cam shaft sensor, everything I’ve heard and the way my mom’s car is running isn’t conducive with the cam shaft sensor but I suppose it might be worth a try? I just don’t know anymore. One friend told me that sometimes you just get a dead hole but I can’t buy that explanation as logical.

Thanks in advance for any information anyone has to offer.

Topic

[Richard Kirshy]

A few thoughts:
Have you checked for a vacuum leak, done a compression test, done a fuel injector test, done a leak down test, ensure the valves are properly adjusted.
Any of these could produce your condition.

[Katie]

I’m kinda feeling like a bit of an idiot right now. One, I wasn’t aware of the search option available on this site. And two, I actually experienced a similar problem about ten years ago with an EGR valve hose that popped off. Feeling like I shoulda known better. Life’s a bit different for me these days being the single mom and sole care provider of my special needs child. It was easier when I could just run over to a friend’s or five until someone eventually helped me figure it out. Gotta remember to utilize my resources. Anyway, thanks so much for the suggestions. I’m gonna try to see what I can figure out tomorrow and will update status when changes. Appreciate your time as I know the value of it.

[Richard Kirshy]

Good luck .. hope it is a simple fix.

[Katie]

Yeah me too since the “mechanic” my uncle sent her to thought it would be cute to copy a page he printed online for an ’03 to ’04 CR-V. I’m not sure how much of a difference there really is between the years though. I thought it was actually codes he gathered. Oh, the saga continues.
Thanks again!

[Author]

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