I had a misfire because the coil pack connector clips broke off when the plugs were changed, so the connectors wiggled loose. Coils, plugs and none of it. Tight valves can cause a misfire, if they're too tight they'll burn and then you'll have to replace valves
Honda P1399: Random Cylinder Misfire Detected
Also if you've ran synthetic oil you shouldn't see so much as varnish in the engine.
I can tell you that your coils are going out
A friend of mine had this issue and we swapped all four coils and it solved the problem But because the coil packs are still in working order, it is nearly impossible to. Had misfire across all cylinders and random misfire code Was abt to change all my plugs when the cel just went away
Idle / hesitation / kangerooing / misfire problems as idle / hesitation / kangerooing / misfire problems and misfires seem to be a common problem on the s2000, and. The plugs on removal where intact, it's the first time i've seen a fully turnable ceramic shaft from top to bottom. The plug was still firing god who knows what would of happened if the coils. On my 2002 s2000 i checked the compression, did a leak down test, changed the plugs, adjusted the valves, tried new coil packs but the cure was the injectors for the random misfires on all or any cylinder.
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So then the tech says he swapped the #2 injector to cyl 1, and 1 begins to misfire some, but cyl 2 doesn't quit misifiring completely
Then they call me and want me to authorize a valve adjustment. I had the same problem random misfires, random cylinders and i swapped injectors for some new ones and it cured the problem i was throwing a cel at the time
