what is the click you hear when the idle rises while car is stationary?

To the techies! 2007 CS. I've been troubleshooting an intermittent "flat" throttle response issue in my car for some time. It's been a ghost without any codes or clear faults. The car is at 100k kms and I believe the throttle is good during open loop mode at start up until car warms up, then it either stays sharp or intermittently go into the flat mode. When it's flat, it feels like someone's plugged my exhaust, even the exhaust note changes and the heal-toe blip rhythm changes (engine doesn't rev up as fast). Have gone through the basics. Cleaned MAF, replaced plugs/coils, fixed AOS, checked for leaks, fuel trims don't show anything other than a slight imbalance. My car does splutter a fair amount on deceleration too. I'm suspecting that I could have a "lazy" O2 sensor as my DURAMETRIC readings are different between Bank 1 & 2 but to be honest, it could be a lot of things like some other sensor or TPS that is affecting the timing. The one thing I am hearing more often is the audible click when the car is stationary and then you hear the engine hum rise slightly like it's powering something then drops back to normal. Idle doesn't look like it changes on the tacho. During this click, I've noticed that the Short term fuel trim sits at "1" like it's flat lined, until it clicks again, then you see the STFT go back to the expected + to - wave. I'm imagining a scenario where the DME is turning a sensor on and off as a "reset". I wanted to do more research to weigh on the different symptoms. Does anyone know the component or technical term for this "click"? Thanks!

-- Thanks for posting; same issue with '06 CS (78k miles) and plan to follow this thread. Daily driver; always serviced; no error code(s); changed out the plugs, checked hoses and connections and still get that momentary pause when depressing the gas...?

A/C compressor cycling?

You'll have to describe what you're feeling a little more and under what conditions. Do you have any speculative theories on what could be happening?

Thank you sir! This has opened me up to more possible causes that I can get hypersensitive too! I started reading about how the A/C clutch could be engaging, even though A/C is not on. This could be very plausible too as when the intermittent loss of power comes on, it can feel like 200kg was added to the weight of the car. Few weeks ago, I had a pulley noise checked out. The mechanic pulled the drive belt off to manually listen for noises and found nothing. The drive belt was about 20k kms old and end up shredding itself on the way home. We thought this was strange but did not think anything of it. The investigation continues!

i believe i have the same noise...sometimes... can you take a quick video of the noise ... upload to youtube and post the link? 2009 Cayman base.

I haven’t paid particular attention to a clicking sound but will begin to take note. My concern/focus has been a momentary flat throttle response - similar to driving w/AC on.. I will also run this by my mechanic next visit as I have mentioned it to him a couple times. I was also able to find a few theories on another site and may post them here. Thx for addressing this issue.

Sorry mate, it's been hard to catch on Video and haven't had time to set up the rig in the car. Basically it's an electrical "click" behind the Right Seat (RHD Driver, LHD Passenger). I tried to describe the click to the mechanic and he said it was a vacuum valve. Searching around, I can't seem to find anything on this other than Tank Vent Valve which is different. Long story short - I end up replacing 4 O2 Sensors which has made my Fuel Trims line up again and eliminated splutter off accelerator, also smoothed out any surging. - My RKAT fuel trim indicate there could be a small vacuum leak that we'll smoke test on next service - Replaced clutch with LWF aasco & Sachs combo. We did find the DMF had failed, to much play, rattling, not springing back. This had smoothed out a lot of things except the intermittent flat response which seems to be persistent per drive (engine start-drive-engine shutdown) but doesn't happen every drive. During the flat response phase, the engine does feel like weight has been added to the engine revs all the way through the range, you hear the induction noise trying to rise but engine is taking more time to rev up. It still revs up, but like the exhaust is clogged. Another issue I need to sort out is the chain tensioner rattle at start up. I'm hoping when the obvious things are done, we end up fixing this. When the car is running well, it's still hella fun, especially with this LWF!

So, what are the advantages of replacing the dual clutch with the single light weight flywheel. I can see that it allows better throttle response, especially when downshifting using heel and toe type of synchronization, but I also read many reports of clutch chatter, NVH and hard to start from standing start without stalling the motor. I autocross, which would lend to this type of equipment, but really do I need to dump the clutch at 4500 rpms and wheel hop for a few feet to get going. Have you added semi solid transmission mounts like Function First Performance upgrade to prevent wheel hop? I can see the benefit of less rotational friction, which may be useful in high torque corners onto the straights. Last week, I could actually bounce the rev limiter in second gear, before threshold braking for an extremely tight right turn flush. I am upgrading my mods to Cargraphics long tube headers with cats, FVD my genious software tuning, Titan 7 TS 5 race wheels with Hoosiers A7's. I also am experimenting with fuel additives, which included Amsoil octane booster +4 to 6 gallons of gas. This additive seemed to add some additional snap to the engine above 4500. I have found that the chain tensioner rattle is oil type dependent. The noisest for my ear is Mobil 1 5W-40 Europeaon blend, followed by Mobil 1 5W-50, then Castrol 5W-50 then Mobil 1 5W-40 FS brand. The lest noise came from Joe Gibbs XP-9 racing oil, (but only for 800 miles) and now AMS oil 5W-40 Signature. I usually change around 3000 miles or when my chains start to make more noise on startup.

-- Thanks for sharing info on this matter as I've been experiencing similar w/'06 CayS and haven't stumbled upon a solution yet. Plan to follow this thread until someone cracks this matter. CFarc

I think you've captured everything Definitely get the sound of a "bag of rocks", when you put power on under 3-4K RPM. I have 996 GT3 transmission mounts (ordered from Carnewal) which have less rubber than the stock and FF engine mount insert. I removed the Wevo's as that was way to much NVH and this set up is much more liveable, raising the notch on the raw feel about 2/10. No so much NVH but that mechanical engine sound becomes louder in the cabin, which I like . I also run numeric cables which contribute to NVH. Living with LWF hasn't been all bad, you do have to adjust. Cons - bag of rocks sound on acceleration under 3-4K RPM - clutch chatter at idle. It's there - Bite or clutch engagement point is higher which has been hard to get used to. It's also feels lighter therefore a little more vague. I can see why some people might feel it's harder for a daily. I definitely take off from 0 normally, no 4500rpm dumps here - It almost feels less torquey in lower/mid RPM, especially in higher gears. I have a tenancy to downshift now to keep it above 3+K RPM if I want to overtake I don't have any issues with stalling in start/stop traffic once you get used to the engagement point but it's less comfortable than the DMF because I do stay more conscious of the engagement point What I do love? - The car feels lighter when you are feathering the throttle, like it's lost 50-100kg and you feel the car shift forward/backward in timing with the on/off throttling. For me, I feel this makes each wheel/strut feel a little stiffer and speak a bit louder to you (like those Initial-D episodes where Takumi is in a zone, the feedback from the car draws a clearer picture of what's happening on the road/bumps). This makes me feel I can turn the car into the corner and move the weight of the car with the throttle to find that feeling of a sweetspot, you feel all 4 wheels have grip biting the road as you power out - 1-2-less3 feels extra punchier as it revs up to 7.8kRPM! I think very slight actual gain but gives me that smiling feeling - Blipping throttle, definitely rev's quicker/freer I may be over romanticising the feeling of a LWF. As with any mod to this car, the "actual benefits" are usually so slight and the LWF is a 1-2/tenth type improvement. For me, It does change the information being fed back to the driver, changing the driving experience. My preference is for a more raw feeling, daily driving and spirited backroads without the discomfort of "race". Overall, you are giving up some comfort with a LWF. We can start a new thread on this as I'd be interested in other perspectives. On the chain tensioner rattle, I think I agree with you on the oil selection being a contributor. The rattle did happen on every first start for almost 18months and 2 oil changes (Mobil 1). I think it's still a sign of an ageing part but most recently I switched to Motul 300v trophy 0W-40 @ 107k kms, then by 109k-kms, start up rattle was gone and hasn't come back. I think it's the oil and tempted to change back to Mobil 1 to validate, but for now, won't look this gift horse in the mouth

I have been thinking about the aasco/Sachs light weight flywheel for a while. Looking at an autocross thread on ********, Sturgus is using one on his recent SCCA STU class build along with Cargraphics long tube headers and MyGenius software package from FVD. He really likes the result of these mods as it adds to his mid range torque curve, which you refer to as gone with the LWFW. That is most likely where I will be heading this fall/winter for next years events. I will be needing a clutch replacement some day, so might as well take advantage of the benefits sooner than later. I will take advantage of your transmission mount 996 GT3 score. So the mod list is; Aasco/Sachs Light weight flywheel, clutch plate, throughout bearing combo Cargraphic long tube catless headers FVD MyGenius Flash Tool with upgrades 996 GT3 Transmission mounts. Suggestions on additional performance is requested.