23 years on the original coil packs seemed pretty reasonable to me. Paying $160 for a single replacement part did not seem reasonable to me.

Backstory: had an intermittent slight miss on light throttle/low-mid rpm acceleration. Seemed to go away in VTEC or full throttle. What was strange to me was that it wasn't always there.

Tried the time honored MAP whack. Didn't work.

Replaced the spark plugs. Noticed that #4 plug (or whatever the closest cylinder to the firewall is) didn't burn nearly as cleanly as the others.

This led me to believe it might be a bad coil pack.. Looked into replacement parts and found that the AP1 specific coil packs were crazy expensive vs. AP2s. In the S2ki Under the Hood section read that '04/05 coil packs would work.

Verified to be correct. Bought a set of 4 NGK AP2 '04/'05 coil packs for the price of a single AP1 coil pack, replaced the #4 pack and the car is running smoothly now.
Might be my imagination but they might sit a smidge taller but still fit under the coil pack cover.


Original on L

Original on right

 

You can get the 04-05 coils which work in the AP1 for half the price
Also if you got the ones from RockAuto like I did ... Mine ran perfect ... until it got cold out. Then it misfires and idles like crap until it warms up but only on colder days. About 1000 miles on these coils. So I started poking around and found that the Densos from Rockauto are highly suspect of being knockoffs (wrong branding, and one user said Denso told them RockAuto is not a listed distributor of theirs) so now I am concerned of the NGKs I bought through them. Cant say for sure my issue is the coil packs, but my OEMs failed, I replaced with these, solved the issue and the cold running issue started 1000 miles later. Car has been sitting a while now so will get around to looking at it soon. Just a heads up though. I will update if I find it is these coils causing the issue though.

Honestly, I would have just gotten the 04-05 units from Honda for $80 each but at the time I was in a hurry.

 

Yikes! That is a cautionary tale. I ordered them from NGK.com which turns out to be *not* NGK but a redirect to sparkplugs.com. Didn't notice until after buying them.

Hopefully they are authentic NGK coils. So far I have a few hundred miles on them and they are still fine. The box of 4 was about $120ish IIRC. Packaging looks legit - at least it doesn't scream fake as I don't know what the box should actually look like.

 

Rock Auto is not an authorized retailer or NGK or DENSO. I have gotten verified NGK fake plugs via Rock Auto a few years ago. sent images to NGK and they confirmed. Sparkplugs.com is an authorized NGK dealer. You should be just fine. I will say the Denso are quite resilient and I recommend and use them often when needed. I hope you kept the good ones as spares.

 

Just a quick follow up - the coil packs are performing well. Car is happy. Now that I no longer have a company car the S2000 shares duty as a part time daily driver. All good in the hood.

 

I've got a box of about a dozen coil packs i hung on to for spares, some ap1 and ap2. There may be 1 or 2 questionable working ones in there as i recall. Id let the lot go for cheap like $50 if anyone wanted them.