This is something that I've noticed with my car 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 1999 so I do not 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.

Car background:

2007 AP2
55,000 miles
original clutch
stock other than Invidia exhaust

While I do most routine maintenance items on this car it does have a 100,000 mile warranty so anything moderate to major I take it to the dealership for. Any help/advice would be greatly appreciated.

 

heat soak possibly

 

I don't believe so. It happens all the time, whether the engine is warmed up or not.

Also another way to describe the jerkiness is "bucking".

 

^^

I've experienced the jerkyness too and it usually happens coming from a stop shifting into second for me... I have seen threads on this before and I believe they sad the culprit was the drive by wire system in the 06+ S.

Don't quote me but I want to say gernby or someone who is familiar with tuning 06+ with flashpro mentioned this and that a tune could almost remove all of this jerky bog/hesitation. I think I had something to do with the computer changing timing drastically to avoid knock??

I'm on my phone but do a search and you'll find the thread. I've learned to just deal with it for now :-/.

 

Happen in 1st or 2nd on partial throttle?
The partial throttle mapping for the DBW is not very smooth.

I had help remapping mine with the Flashpro and now the partial throttle is sublime-really smooth and nice.

 

If the cause is the drive by wire throttle then why is this just occurring now? I didn't have this problem 2 months ago.

 

Can you post your mapp, I would like to look it over please?

 

This might be a quick fix.

https://www.s2ki.com/s2000/topic/492...ean-iac-valve/

Mine does this too every great now and then so I'll probably pull my IACV when i replace the cat in a couple weeks to see how dirty it is and clean it.

 

Try the above, and also try cleaning your intake and MAP sensor a bit. I have/had similar problems recently. Cleaning my MAP sensor area has helped a lot. I had the same problems you were having and after a few weeks I eventually threw a code for a faulty map sensor. I cleaned it up and it has improved a lot and took care of the CEL. I'm still not running 100% normal yet. I'm going to try the IACV DIY above and see if that fixes me.

 

Have you had any luck, Wolfpack? I'm having the same problem right now and I'd like to see how you fix it.