Stko0k

Ive been havin a very wierd misfire/stutter....it does it at low acceleration....i thought it could be the plugs so i ordered some new plugs ( Pk22PR-L11S) (3284 Desno Plugs) which is equivalent to wut the plugs the dealer sells. First half hour i drove with them it was fine. Again it gave me that wierd stutter at slow acceleration....or when i came to a complete stop the idle would drop VERY low or sometimes just turn off...i could definelty smell somethign wierd which smelled like a "missfire"

I never got any kind of CEL except for once and that was:
P0172 System too Rich (Bank 1)

I thought it could be the coils....my buddy at the junkyard had a set for a new civic so i borrowed them it gave me the same problem...although im still considering changing those to a s2000 one but the problem was still the same...i tried the map sensor whack thing...and i had a brand new map sensor i put on....i tried putting different plugs.....diff plugs react differently some drive a little smoother even though they r OLD plugs..but at the end i get this wierd misfire....i dont know how else to approach this situation....

Ek9

The CEL tells you pretty much where to look. The smell, the symptoms. They're all pointing to the O2 sensor first and maybe the Map second. Your new plugs are probably fuel-fouled now and you'll likely need another set (or just the opposite and you're running lean as hell because the O2 is lying to the ECU).

You need someone with a real scan tool to look at the sensor readings. I had something similar happen to me and it was a bad O2. Bad in a weird way, it was out of cal but, still worked. The computer thought the O2 was good, was trying to drive the mixture the way the O2 sensor said too and it ran like crap. New O2 and it was solved.

I saw it by looking at the short term fuel trim on a scanner. Should have been close to 0% was more like 20. Ditto for the Map sensor. Make sure the computer's seeing reasonable numbers from the sensors.

Stko0k

i kinda of tried the o2 problem with a universal o2 sensor..and i switched it between the 2...first i tried the one before the cat....same problem...then i put the old one back and changed it with the 2nd o2 still the same problem....it was a bosch universal one...as far as the map sensor...i put in a BRAND new map sensor from the dealer.....

xviper

I might be wrong in this case, but I think you are chasing "wild geese". The dipping idle when coming to a stop is very common and has been discussed here quite a bit lately. This is common, particularly if you've been subjected to high ambient temps and thus, high under hood temps. The key here is to NOT try to help it by giving it gas to "save it". Let it dip down. It will "learn" after several episodes. If you continue to give it gas, it will get so confused, it will actually kill. When it does die, let it. Then re-start with NO gas pedal intervention until it stabilizes the idle on its own.

Your other symptom of odd stuttering when accelerating at low speeds is also very common. Do a search for "bucking" or "kangarooing". This is partially due to "heat soak" and the intake being filled with very hot air. This can be corrected by a slight modification in driving technique.

I believe you may be running around trying to fix something that isn't broken and trying to find a complicated solution to a common and simply characteristic.

Stko0k

My car doesnt move...it sounds normal.....it hits vtec.....but the car is holding back.....how is that not a problem? the car bounces up and down as if it were to stall...the car shuts off..i turn it on its at 200 rpm...it adjusts for a minute..i drive...come to another stop..it turns off again.....driving technique? i highly doubt it.....somewhere along the line...the air to fuel mixture is not correct.......its either not gettin spark....not getting fuel....or not gettin air....or its gettin to much of one or the other....

this problem didnt occur as often in the begginin it started doing it more and became way more noticable over time

xviper

YES. Like I said, "I could be wrong" in your case as you don't describe your situation in detail. But YES, this is a well known thing that has been hashed out for years.
Are you ..................................... ?
Going along in stop and go traffic? Is it hot outside enough to make for very little air flow through the engine bay (so it's getting hot under the hood)? Are you slowing down to the point where you are getting near engine idle rpm? Then you see the traffic ahead move along and you just give it gas to catch up? At that point, the engine sort of lugs and the car "bucks" back and forth and you feel like an idiot? It will continue to do this till you put your foot on the clutch and start over again like you are taking off again? This is a situation where the hot air in your intake is making the engine bog at or near idle. You then open up the throttle plate to try and make the engine rev up and make the car go forward. It is so close idle that the sudden opening of the throttle plate compells the engine to speed up, but it's trying to move 3000 lbs of car at a time when the hot air is simply unable to produce a good combustion. The ECU can't make up its mind whether to idle or to speed up based on all the sensor readings it's getting, so it bounces back and forth between idle and revving. Did I get any of this right?

Look, I'm not going to argue with you on this. You do what you must. I'm just saying to do search for those threads and you may be able to see a simularity to your case. If you think it's a "problem", then chase away. People have been "chasing" this thing ever since the S2000 came out.

Ek9

Assuming something's wrong. I'm taking your word for it but, xviper knows and aweful lot about these cars. I wouldn't discount his comments.

Without a scan tool, you're probably not going to fix this. I keep mine in the trunk of the S2k (I mean I stuck it there and forgot to take it out). Decent one like the AutoXRay's not that expensive. I wouldn't even consider working on a modern car without one. Otherwise it's just a crap shoot.

With your symptoms it could be 1000 things or nothing. Just swapping parts out isn't going to solve it.

xviper

Looking at this post of his:
I get the feeling that this was an isolated CEL and he doesn't actually have it at the moment, in which case, there may be no code to scan. These are some of the details (that were left out) of which I spoke.

xviper

OK, I had a little time and found that "bucking" thread:

http://forums.s2ki.com/forums/index.php?showtopic=57405

Stko0k

i am not discounting anyones comments or arguing with anyone...and i know wut he means by the driving technique as well....that happens to me sometimes....i do appreciate everyones comment or idea.......the thing with the CEL is it came on once and then i checked it....however next morning i turned on my car the CEL was off.......