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Got this free cause nobody could fix it. That said I was born with a wrench in my hand, thanks dad:P Facts: It has no spark at cylinder one, code 301. Parts replaced so far not by me. Coil and NGK 6441 all new. Parts I've tried so far, used ECU flashed and installed. Same skip and code no change at all. Alternator and all bolts are perfect, I was made aware of this by peps here thank yous. The car is a one owner, 149k and very well maintained. Women owner who I think never got over 3k rpm. The signal wire form the ECU I'm thinking is broken or the coil connector is bad. I did swap coils and plugs around and the skip stayed on number one. This is a real nut buster guys. I'm searching for ECU wiring diagram next to check continuity of plug one. I'm not sure what else to do at this point.

 
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Tested the signal wire from the unplugged ECU to cylinder one and found 150k ohms. That's basically open, all the other cylinders tested good. I'm thinking it's on the engine side of the harness so starting there, but I may just pull the whole harness out. This would make it easier to repair and tape back up in the long run. I'll post pics when I find it. I found a lot of acorns in the air box, but see no wire damage to the harness so far.

 
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good luck.

 
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When I got my son his first car, a 1998 civic, we had a troublesome electrical issue like that at some point. We pinpointed it to something in the ignition and I couldn't see the problem, but my son with his hawk eyes noticed that a very fine wire was damaged, and once we cut and resoldered it the problem was fixed. We did have to unbundle the harness in the engine compartment to expose all the wires and they were all very thin, so it took a lot of patience to find the culprit!

Many years later, my wife's Yaris lost her rear lights and I couldn't see where the wire was broken... Then I remembered what can happen to thin wires, so I carefully checked the wire inch by inch until I noticed a small dent - it wasn't cut, it just had been squished slightly, probably during installation and it took 12 years of road vibration to finally break!

Come to think of it, detectors exist to narrow down breakages in live wiring, they're used in household electricity, but I'm not sure they'd work with automotive DC.

Take a deep breath, take your time and Good Luck!

 
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There's the broken signal wire not even close to a connection. The harness takes a hard right out of the firewall and that's where the break was. Had to trim an inch off to get to good copper, but she purr's like a kitten now!

 
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Looks almost exactly like what happened on my son's 98 Civic 😮😮😮 ... The only difference is the wire showed no signs of bending and was broken in the middle of a straight run, so I surmised it had simply broken from internal friction... It had been driving me nuts ("Tabarnac!" ), so many small wires to sift through and no idea where the break could be... I just couldn't see it and was going to quit, then my son who at that time had never had a wrench in his hands, casually glances over my shoulder, immediately singles out an orange wire with the slightest patch of exposed copper and simply says "Hey, Papa, check ça!" 😆 ...

Fond memories! I miss my son, but he's forged a life for himself out West in his beloved mountains... He only had the car for two years, but in those two years managed to add 120,000km on it delivering pizza after school so much so that he ran it into the ground, too many things to fix in the end, but it allowed him to save enough money for his big move out West... He told me recently he regretted junking it, so much so that got another one later on, but it wasn't the same, the charm was broken and he didn't keep that one...

 
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glad you found the cause!
tracing electrical issues is really tough, but if the common sensors going out don't solve the issues... hunting damaged wires is needed, but most people just balk at it and keep changing sensors, so great job there!

 
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Much respect to those who can troubleshoot electrical problems. Nice work!

And is that a Tekton swivel ratchet in the pics? I have all three sizes of it myself. Great tools for DIYers.

 
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YES! Just replaced all sets and ratchets with Tekton.

 
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Thanks! I love this kind of problem.