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slight hesitation on accel at 3k rpm (991 base, MT)

 
Old 03-26-2014, 12:46 AM
  #31  
Tapeworm
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I have a 2013 C4S PDK and have the same issue. It really felt as if the engine hard a hard time breathing around 2,800 rpm. Now my car is run in, and after a software update from the dealer, the problem is significantly less. Originally it felt awful, now it's far, far less noticeable.

I think it's fuel mixture (which is maybe why it appears less on cold engines) coupled with variocam engagement and poor tuning biased towards emissions. Maybe they are trying to run 'closed loop' with the O2 sensors on partial throttle and just can't achieve a smooth engine with variocam in this mode....?

Andy
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Old 04-20-2015, 08:53 AM
  #32  
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Originally Posted by MMK110464 View Post
I have a 2012 997.2 C4S and it has been doing the stumbling/hesitation at around 3k rpm since I bought it.

The simple procedure outlined below has eliminated the problem for me almost completely.

As you all know, the car starts the auto idle procedure when its been parked for several hours (which is usually the case in the morning when the car is started for the first time that day) and the revs go to approximately 1,500 rpm for about 1 minute. When this happens, I immediately blip the gas and take the revs to between 3-4k rpm. This will deactivate the auto idle and the revs will fall to its normal level of 800-850.

Thats it. This procedure will keep your car stumble free as long as the auto idle is not allowed to engage.

Please give a try and give your feedback
Found this thread after a Google search, trying to find any help on this engine condition, stumble, misfire thing. THIS procedure actually works!! I can still barely feel a little something when the tach sweeps past 2800 but NOTHING like before! I was to read point it was really bugging the **** out of me! For whatever reason this definitely has helped if not almost completely eliminated the issue for me. I find it doesn't take that much of a rev to kick the idle down, anything close to 3k will knock it down. Give it a try.
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Old 04-20-2015, 11:20 AM
  #33  
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Originally Posted by wheeler View Post
Found this thread after a Google search, trying to find any help on this engine condition, stumble, misfire thing. THIS procedure actually works!! I can still barely feel a little something when the tach sweeps past 2800 but NOTHING like before! I was to read point it was really bugging the **** out of me! For whatever reason this definitely has helped if not almost completely eliminated the issue for me. I find it doesn't take that much of a rev to kick the idle down, anything close to 3k will knock it down. Give it a try.

WOW I have to conscientiously try this and then pay attention to the car. It bugs me from time to time and when I feel it I usually downshift for a few minutes and it goes away. 13 C4S PDK
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Old 04-20-2015, 11:46 AM
  #34  
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Mine a manual, 997.2. It can really jack with you when driving more mellow, like in traffic. Seem that 2nd gear shift rpm lands right in that 2500 range, you get on the gas a little and it falls on it's face and bucks the car. Ridiculous a company like Porsche can't figure this out. My buddys 996 GT3 pulls away as smooth and easy as a honda civic compared to my car!
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Old 04-20-2015, 12:32 PM
  #35  
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Take it to the track or hard drive on the back roads keep rpm above 4k for at least 4 to 5 minutes then go for engin flush and oil change.

That fixed the histation on my 997.2p

These cars are designed to be driven hard
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Old 04-20-2015, 12:38 PM
  #36  
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Originally Posted by Porluv View Post
Take it to the track or hard drive on the back roads keep rpm above 4k for at least 4 to 5 minutes then go for engin flush and oil change.

That fixed the histation on my 997.2p

These cars are designed to be driven hard
You're preaching to the choir. My car rarely sees rpm below 4k regardless. Has nothing to do with an Italian tune up or oil change. This is a mapping issue with the cars.
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Old 06-07-2015, 01:29 PM
  #37  
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It is about gas mileage--below 2800 the valves open less than they do about 2800 rpm. Less valve opening means better gas mileage.
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Old 08-20-2015, 03:04 AM
  #38  
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Default Blips and hesitation at 31-3300 rpm

Wheeler...that is on egorgeous auto you have there...do tell me what it is...duck tail? No emblems...awesome.

I have an 02 c4S that does this. Going to try that little start her up trick.

I have also heard that aftermarket exhaust and cats and such will make this issue even more noticeable. My tuner tells me that a good zoom in on the curve at those rims can smooth out...I have yet to try this...sure would like to "borrow " somebody's cable and software and re-tune my engine...bought it with fvd stage 2 on it and I can't touch it without paying another 850-1000 to buy a new tune kit...

Anyway...folks are in MCI area... Ex 930 operator and current Macan guy ... That's mi dad...me, only 911.
Pb
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Old 08-20-2015, 09:19 AM
  #39  
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Thanks man, 09 C2S, pasm, lowered on H&R springs. Getty sport duck tail. Love it!


Originally Posted by Phoenix604 View Post
Wheeler...that is on egorgeous auto you have there...do tell me what it is...duck tail? No emblems...awesome.

I have an 02 c4S that does this. Going to try that little start her up trick.

I have also heard that aftermarket exhaust and cats and such will make this issue even more noticeable. My tuner tells me that a good zoom in on the curve at those rims can smooth out...I have yet to try this...sure would like to "borrow " somebody's cable and software and re-tune my engine...bought it with fvd stage 2 on it and I can't touch it without paying another 850-1000 to buy a new tune kit...

Anyway...folks are in MCI area... Ex 930 operator and current Macan guy ... That's mi dad...me, only 911.
Pb
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Old 08-22-2015, 07:27 PM
  #40  
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Default tried the start up thi8ng

did not work for me...well...maybe it did, but not all the way gone...I could not get the auto idle to disengage and I thought I timed it perfect...did it several times to try to get it to disengage, but I don't know that I did it successfully...

I think it is just a fact of life on some cars and not on others. Also more noticable on aftermarket exhaust...

My neighbors likely hate me for my early morning throttling to get that auto idle up to come down...

pb
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