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WOT stuttering?

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Old Jan 22, 2011 | 08:51 PM
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WOT stuttering?

Hey guys,
Had a tune in the past few months and the car would slightly studder under hard acceleration.
then went stock for a few days and the car wasnt really stuttering...

However just got a new tune 2 days ago and the car seems to be stuttering a bit under hard acceleration. Sometimes it gets really bad to the point that the car shakes back and forth basically.

Car is making 17psi boost all the way thru with sport and 15psi without sport.

I have heard this could be caused by
1)Spark plugs
2)coilpack
3)MAF sensor
4)loose boost hose

What do you guys think?
 
Old Jan 22, 2011 | 09:05 PM
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Could be a crappy tune and causing detonation so your ecu is pulling timing...

Who's tune?
 
Old Jan 22, 2011 | 09:21 PM
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Originally Posted by TestJet
Could be a crappy tune and causing detonation so your ecu is pulling timing...

Who's tune?
Powerchip
 
Old Jan 22, 2011 | 10:02 PM
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Which gear are you sensing it? Your stability management may be cutting in.

Try with your PSM off.

Happens to me all the time in 5 and 6th gear under WOT unless I turn PSM off.
 
Old Jan 22, 2011 | 10:54 PM
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Agree, crappy tune or plugs.
 
Old Jan 23, 2011 | 10:27 AM
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Originally Posted by sam12345
Sometimes it gets really bad to the point that the car shakes back and forth basically.
Clutch issues?
 
Old Jan 23, 2011 | 04:46 PM
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How fresh is your fuel? My car was doing the samething when I had old fuel in it.
 
Old Jan 23, 2011 | 05:58 PM
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Datalog your AFRs.
 
Old Jan 23, 2011 | 07:07 PM
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Originally Posted by venkatreddytx
Which gear are you sensing it? Your stability management may be cutting in.

Try with your PSM off.

Happens to me all the time in 5 and 6th gear under WOT unless I turn PSM off.
Happening in all gears with PSM off


Originally Posted by TTdude
Clutch issues?
It very well could be clutch slipping a bit as well...

Originally Posted by Porsche997TT
How fresh is your fuel? My car was doing the samething when I had old fuel in it.
Fresh 76 fuel, couldnt be a fuel issue


Originally Posted by bbywu
Datalog your AFRs.
Will do. thank you.
 
Old Jan 23, 2011 | 07:14 PM
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Originally Posted by sam12345
It very well could be clutch slipping a bit as well...

Fresh 76 fuel, couldnt be a fuel issue
Don't think a slipping clutch will cause stuttering. Revs jumping under load without corresponding acceleration is more symptomatic of this.

Just because you just pumped the fuel does not equate to 'fresh'. You have no idea how long it's been sitting underground. That being said, it's unlikely to be this rather that one of the other aforementioned reasons.

My vote goes with bad tune and/or plugs.
 
Old Jan 23, 2011 | 07:27 PM
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Probably plugs. Go one range colder than stock
 
Old Jan 23, 2011 | 07:33 PM
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Most likely plugs and perhaps coilpacks...might as well do both at the same time.

MAF might need to be cleaned as well.
 
Old Jan 24, 2011 | 01:24 PM
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Definitely change the plugs if they're suspect. We often see coils cracking and corroding depending on the age and the climate they live in.
 
Old Jan 24, 2011 | 03:33 PM
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Plugs...
 
Old Jan 25, 2011 | 02:00 PM
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ok so i am setting up an appointment to get the sparkplugs changed to the denso 20 p8.

however i am debating whether or not to do coils. what are your guys thoughts?
 


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