I had a post a week ago with my ap1 s2000 misfiring i havent solve the problem ive changed plugs, check coils seem to be fine, redid my valve lashs twice....car doesnt idle but it misfires from motor and exhaust like any normal misfire....my last situation before i started to misfire was from driving the car to EMPTY which i remember i did that day then later notice slight misfire after driving car to E....then the next day the check engine came on...could this be residue from gas tank which ended up in the injectors thats my theory for now my new theory to be exact...i havent owned the car for long so i cant say wat gas or so has been pumped into the car....so ive poured one bottle of techron injector cleaner into the car ive done research on forums saying yes it works and it doesnt but hey i was planning to pull the injectors off anyways so mine as well try the injector cleaner after a good 40mile freeway drive misfire went away did i mention this problem comes and goes it can run fine for one or two days then misfire...drove it for another 40 started to misfire again so ive poured another bottle...and ive done this all on a half tank with the additive thus i dont believe it to really take effect with a full tank...i deal with chemicals alot and if i was to pour that small of a bottle in a full tank it would be worthless to me in general...ive noticed way way more throttle response and smoother acceleration cause my Ap1 didnt seem to run right...again after second bottle and another 30miles it has gone away but im not saying it works yet just need my fellow S2k owners inputs and thoughts..as i know alot of s2k owners have this problem it seems...

 

Put a scanner on it and check the codes..

 

i have a scanner codes are p1399 p0300 o0301 p0303 most of the time

 

After doing all of the things you mentioned, mine ended up being injectors. Not to mention you said that it started right after running the tank empty.

 

I had those codes too, and after trying a bunch of other things it ended up being the fuel injectors. I had the codes for a long time and after I replaced the injectors I never saw another code. It's been two years now since the last misfire codes.

 

k, before you do anything, buy a injector, a coil, a fuel fitler, you need to actually know whats making the misfire, if you can't do a leak down and compression test, any decent shop can for little money. If those are fine, then you can start digging into fuel presure test, or bring the car to a honda dealership to get freeze frame information. A lot of shops honestly can't handle this issue, most of the time they replace some injectors, a week later, a bill later you get cel/p1399, etc

do the comp and leak down. that will narrow it down a lot, post results and we will fix this.

 

Read through this post, lots of good info (click here)

I might have missed it, but have you tried changing the coil packs?

 

updating post for s2000 owners interested in this problem......cars been running fine for now although id notice idle drops low still car did die once from that cause....most likely a Map or IAC problem for that...i had it map whacked already LOL......more updateds im not crossing no fingers yet........lol