This is something that I've noticed with the S2000 for the last few weeks. Obviously someone that is not driving a car with a manual transmission properly will experience some jerkiness but I've had this car for 3 1/2 years and haven't driven anything but standards since '99 so I don't believe my driving skill is the culprit here. At first I thought I was just having 1-2 of those random bad days with shifting. However the problem has persisted and no matter how I drive the car unless I gradually increase the throttle there is some jerkiness that resonates through the drivetrain. It even makes the engine rpm dip for just a second as a side effect (easily felt and heard through the exhaust note).

Anyone have any suggestions? Perhaps a broken transmission or engine mount? I had a buddy look at my engine while revving it and it looked secure. Of course that was while in neutral and under no load. I just took the car on a 1200 mile trip and it performed flawlessly except for this issue.

I posted this query over on http://www.s2ki.com and the best reply I've gotten so far states that it may be a Drive by Wire throttle issue. Apparently the DBW tune isn't that great for partial throttle applications. I could see that being the case, but do not understand how that could just become an issue now (seems like something that would always be a problem).

I might just take the car to the dealership (under warranty) but it seems like a very difficult problem to describe to those knuckle draggers. Any thoughts from the wise men that frequent this forum you jerks?

9/6/2012 4:22:36 PM

I am having the exact same problem on my 99 Honda Accord V6. I was originally told it was my engine mounts causing stress on the drivetrain. I replaced my motor mounts this past weeknd, all 4. The problem has not gone away but after the mount replacement it doesn't happen as often or as bad as it was before.

9/6/2012 4:31:14 PM

You need to let me check it out.

9/6/2012 6:42:34 PM

changed the spark plugs lately?

9/6/2012 10:16:16 PM

Mine isn't dbw and has a fairly bad part throttle tune . Not as bad as you describe though.

9/6/2012 10:19:24 PM

Corrective action: Remove F20; replace with LSx. Minimize use of partial throttle.

9/7/2012 12:23:20 AM

^^^^sure if you have the time next week let's set that up

^^^I have not. Still have the originals in place (55k on car)

^perhaps you mean F22?

9/7/2012 8:36:36 AM

change the plugs

9/7/2012 9:07:50 AM

Yeah guess I could do that. Definitely an incredibly easy fix (if they're the problem).

Doesn't get much easier than changing out plugs on an inline 4!

9/7/2012 10:00:30 AM

clean the MAF (if you have one)

9/7/2012 10:23:04 AM

I do.

Out of curiosity though wouldn't a dirty MAF result in decrease in fuel efficiency?

9/7/2012 10:48:33 AM

i've seen new spark plugs fix partial throttle bucking/sputtering many times. with 55k it's about time to replace them anyway.

9/7/2012 11:07:15 AM

Quote :

"i've seen new spark plugs fix partial throttle bucking/sputtering many times. with 55k it's about time to replace them anyway."

I can attest to this. I had similar issues with the Mazda. Some of the plugs were out of spec. I re-gapped them and the car ran a lot smoother under partial throttle.

9/7/2012 1:01:56 PM

AFAIK all honda engines use MAP sensors.

9/7/2012 1:14:03 PM

ah my bad. get those 2 confused sometimes

9/7/2012 1:31:24 PM

so the slight jerk i have in my accord might just be spark plugs? i certainly haven't done anything to them and i've owned it from 90-140k right now. good to know

9/7/2012 1:33:57 PM

Hello, WolfpackS2k

9/7/2012 2:57:41 PM

9/7/2012 3:11:00 PM

i just put new plugs in 15k ago, 15k ago i did the entire secondary ignition system, plugs, wires, distributor cap and rotor

9/7/2012 4:36:34 PM

While usually they'll give a misfire code I found recently one of my coil packs was on its way out. Always stuttered on partial throttle but full throttle and idle was ok. That wouldnt apply to you trigger since u have distr but i didnt know if the S2000 had them either. The misfire from the coil pack ended up bridging that cylinders spark plug in the process even after i had just replaced them 10k miles before I found the coil pack issue.

[Edited on September 7, 2012 at 4:59 PM. Reason : summary: replace plugs first then check coil pack resistances or visually for cracks or buildup]

9/7/2012 4:58:17 PM

Map + coil pack on s2k

9/7/2012 6:09:40 PM

Replace plugs, then individually test coil packs if problem does not go away. I had a similar issue on the Marauder that drove me sort of crazy because I replaced the plugs, no change, but it wasn't throwing a code. After it had been doing it for many months and after an unrelated issue, it finally threw a code one day, ended up being the #2 cylinder coil. Smooth as glass afterward. Wish I had tested them all as a precaution.

9/10/2012 3:20:44 PM

I had the same problem on my e36 M3 and I had a bad ignition module/coil pack on one of my cylinders. I ended up just replacing them all and it fixed the issue.

9/10/2012 5:16:53 PM

I HOPE IT'S YOUR VALVES

ok, that's just wrong.

9/10/2012 5:27:40 PM

^damn son

Last few replies, you guys talking to me or trigger?

9/10/2012 10:40:55 PM

Sounds to me like you are describing the side effects of your engine shrinking two sizes smaller. Less power=now you are lugging the engine. Wouldn't take much of a reduction in power to make this feeling evident in a S2000. When did you tune it up last? Have you replaced the upstream O2 sensor?

Does this car even have power steering? (random I know)

9/11/2012 12:51:21 AM

Pat I was talking to you

9/11/2012 10:52:03 AM

^thanks Jared

Quote :

"When did you tune it up last? Have you replaced the upstream O2 sensor? Does this car even have power steering? (random I know)"

This is a Honda and it only has 55,000 miles so nothing on the engine has required maintenance (nor is any called for). Following the service manual only calls for fluid replacements up to this point in the vehicle's life. I'm not saying your suggestions are wrong btw, just that any engine tuning at this point would be uncommon. And wouldn't a faulty O2 sensor trigger the CEL? (which has never come on).

And yes this car has power steering. And electric power steering, not hydraulic. Which is unfortunate b/c EPS sucks for feedback.

Let me restate that the problems I'm noticing is subtle. I would hope that it is something a technician would pick up on but I honestly am not sure they would.

Oh, and have I mentioned that my convertible top has a hole? (2nd top) Fucking Honda cannot make convertibles for shit

9/11/2012 11:39:23 AM

^ Yeah, Honda convertible tops suck. I highly recommend a Robbins stayfast (canvas) soft top. It's a beautiful upgrade over the standard vinyl and should last way better.

9/11/2012 1:20:05 PM

I'd like a Robbins when mine finally gives out - thankfully, though, I replaced the elastic in the top and only have to deal with a TINY pinhole (9 years, baby). Probably going to try to use vinyl glue of some sort to see if that'll patch it

9/11/2012 2:07:32 PM

TKE-Teg I was talking to you also. Especially considering mine didn't throw a CEL until very late in the game, but it definitely did turn out to be the coil pack.

9/11/2012 2:08:50 PM

My bad coil pack did not throw a CEL either

9/11/2012 4:01:02 PM

^^&^interesting to note

^^^the AP2 has a factory service bulletin for a top manufacturing defect. AP1s do not suffer from this. Your top is merely old

^^^^I doubt I'll get a Robbins top unless the warranty company or Honda wants to spring for it. Either way I'm not paying and I don't intend to keep the car long enough for this to happen again.

9/11/2012 11:13:27 PM

Top is doing better than the motor, too

[Edited on September 11, 2012 at 11:20 PM. Reason : ]

9/11/2012 11:20:31 PM

Hey hey hey, stop bumping your thread above mine!

9/12/2012 5:08:28 PM