AdamSanta85

Rich mans VTEC

Joec500

at least the parts don't carry the PTax

97supratt

rnl

it's gone. it's working perfectly now

duxsi

@rnl Could you please be so kind as to take a minute to explain your exact symptoms to the rest of us.

You wrote "The stumbling issue occurs at higher revs....."
I'm not aware of anyone stumbling at higher revs, so are you describing your issue or did your symptoms occur at 2500rpm and below?

You also wrote "..for this problem the car only was smooth at rpm greater than 2500". This implies that you had an issue in the 2k-3000 rpm range. Is that correct?
Most stumblers complain about a stumble (non-linear power delivery) between 2500-2800 rpm and not at higher revs.
Thanks in advance..

rnl

Rough idling and acceleration at low speeds. Tended to smooth out after the engine hit 2500 rpm.
This is not like the undiagnosed stumble encountered by some.

Car now idles smoothly,. accelerates crisply

duxsi

Thanks for your response.

ICU991812

Looks bad, but actually quite easy. Once the wheel is removed, two torx on each heat shield (two shields) to remove. Then two smaller torx on the solenoid and out it comes. Disconnect, connect, and reverse and done. I did everything in less than 30 minutes. Only need a ratchet and several extensions. Didn't even need a universal.

The symptoms for me were the misfire codes on one side of the engine, and engine stuttering when idling and starting from a stop. It came and went, but finally got sick of it like two weeks ago so just put aside an hour to get to it. As said, only needed 30 minutes from wheels up to wheels down.

So far, about 500 miles and drives smooth. I noticed before when the I stopped a little harder, the PDK downshifted with noticeable shifts. Now, it smooth up and down. So, it might be all related as part of engine management.

JW911

Very interesting. I have the low speed/from a stop stumble. I am pondering doing this. Would cost me about the same as bringing it to the dealer and having the mess with it for an hour and then tell me they can't find a problem. Anyone else cure a low speed stumble with this repair?

ICU991812

Does yours just stumble all the time and no CEL code comes up? Mine would be fine, until it stumbles. And stumble meaning high revs seemed fine, but when slow to a stop and move again, it would stumble and putt around until I got over 20 mph. Eventually a CEL comes on and the code was for misfire cylinder 1, cylinder 2, cylinder 3, which is driver's side. I changed it and running much smoother then even before when it was running fine and PDK shifting better too.

JW911

No codes for me. Just hesitates from a stop and I feel like low rpm torque is wimpy and I could swear it was more torquey at lower revs. Mine is a 3.8 with 62,000 miles. High rpm no problem, she screams and throws me back in the seat. Noticed this issue about 5,000 miles ago.

Scottg1le

I have felt like my 14 C4S has had a stumble below 4k rpm under light to medium throttle. No codes thrown, but it just feels to hesitate during acceleration. There is also an audible skip or cough that can be replicated pretty much on command when the throttle is changed from light to medium in the 2500-3500 range. Above 4k the car screams and there is absolutely no hesitation but I would love for the car to be smoother under 4k rpm. I have thought maybe it needs a PDK clutch, but I may change these as it seems like an easy DIY. Thanks for posting!

rnl

yup, those were the early symptoms

rnl

I brought my car in to the dealer when I noticed this happening and probably because no codes were present they said - bad gas...the hiccup in the 2500-3500 range is key

ICU991812

yes, because it doesn't always happen, you might think it's something else like "bad gas" or "cold morning" etc. I had it happen when right after getting off highway. It stuttered and drove strange. I pulled off and then thought maybe it was bad gas. Filled up on Sunoco Ultra and right after it ran better. So I thought bad gas. Then on way home it acted up again and CEL came on. I'm sure there are other causes for hesitation, but this is probably easiest to fix.