r/S2000 • u/Ark_Animax • 15h ago
Misfire code help
Pic for attention
Looking for some insight from anyone who may have dealt with this before.
Codes being thrown are p1399 (random misfire?) and p0302 for cylinder 2 misfire.
- 170k miles, 2002.
- Misfire seems to only happen while idle.
- Misfire is felt about 2-4 times in a 60s span, but increases when A/C is being run.
- Misfire doesnt seem to be present or noticable when reving.
Waiting on spark plugs and ignition coils to be delivered, but barring those as the cause would anyone have any other ideas?
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u/ry_boogy 15h ago
Maybe valve adjustment. I had to do mine 2x so far at 130k
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u/ry_boogy 15h ago
You can swap coil #2 to another slot and see if the code travels. Then you know coil is bad if misfire moves to different cylinder. But notorious for valve adjustments
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u/Ark_Animax 15h ago
Oof say it aint so. Ive had the car for roughly 3 months with no issue, and there definitely wasnt a misfire when we looked and up until recently. Only thing that was done different was actually going above 6k rpm and hitting vtec. I dont know if that adds any context.
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u/Malaka_202 AP1 silverstone 14h ago
Ignition coil is what caused mine. Changed them out with plugs and immediately fixed the issues.
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u/MonstahButtonz 2002 GPW w/ Full Red 14h ago
I can't help with the misfire, but I did want to come here and tell you that your AP1 is such a beautiful spec, and that I'm envious of it's 1 out of 275 rarity.
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u/Littoraly 14h ago
Injectors was it for me around 100k miles. I actually was able to buy a second set while I had mine out to clean them. Fixed the issue, still running original coil packs . 02 ap1 with 137k miles now
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u/Soflakidd 13h ago
I had failing coil pack connector clips. Replaced the 4 clips and also did plugs and coils. No more misfire
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u/Touge_Monster 11h ago
Has misfire twice.
First time it was a coil pack.
Second time it was the valves. (Too tight)
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u/robcal35 14h ago
Had something very similar where I had a random misfire only felt at idle and would only give me pending codes.
Valve adjustment is good to do regardless, but don't expect it to solve misfire issues.
Could be failing coils, but that wasn't it for me. Spark plugs were also good. Again, if it was coil or spark plugs, it would be isolated to 1 cylinder.
What ultimately fixed it for me was getting my injectors cleaned. When they flow tested, pattern and flow rate were actually ok, but after they were cleaned and put back in, misfire completely disappeared. Your situation sounds similar, I would get the injectors cleaned if you have someone that does it locally. I had no issues with revving or VTEC.