Misfire under high rpms
Thread Starter
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Joined: Jun 2010
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2007 s600
Misfire under high rpms
Has anyone with the V12TT experienced misfire codes under load around 5-6K rpms? My car is an '07 has 61K miles, ran like new. Now whenever I get on it, it throws misfire codes and the motor idles rough. I turn it off, restart and everything is back to normal ?!?
What could cause this ? Could it be a dirty fuel filter, MAF sensor, O2 sensors, etc. ..or is it a coil pack. One could spend endless amount of money and time on this and the problem most of the time does not go away. If it was a coil pack, wouldnt it be doing it at any rpm level.? I'm really stuck with this on.
I appreciate anyone with any help. Thanks.
What could cause this ? Could it be a dirty fuel filter, MAF sensor, O2 sensors, etc. ..or is it a coil pack. One could spend endless amount of money and time on this and the problem most of the time does not go away. If it was a coil pack, wouldnt it be doing it at any rpm level.? I'm really stuck with this on.I appreciate anyone with any help. Thanks.
Thread Starter
Member
Joined: Jun 2010
Posts: 116
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2007 s600
If I use Star DAC, will it pinpoint the problem or just give you codes? A good possibility is that it could very well be a coil pack if the codes show only one side of the motor. Did anybody get misfire codes from both sides of the motor? I doubt that both coil packs are shot.
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Joined: Nov 2004
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From: Illinois
GL550, C55, 335i Coupe, vintage Mustang
I'm going to guess you have a valve floating. You probably have a misfire on one cylinder that doesn't occur under normal driving, but as soon as you wind it out in third gear, it starts making a sound like a really crappy running Dodge Viper. On a good note, the parts are cheap, I would replace all three valve springs on the offending cylinder. Labor-wise, you need to find a good V12 tech, because the average dealer tech will want to remove the cylinder head(which involves removing the engine from the car). I've done 2 V12 cars that had the same issue, but one did it at 3k miles, the other at 17k. Let me know if I can help you out any further.
Nick
Nick
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Thread Starter
Member
Joined: Jun 2010
Posts: 116
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2007 s600
Yes. It was a vacuum hose that was causing the misfires. It looks like the small hose on the right side of the engine was dry rotted a little, came loose, and had a leak. Why didnt MB use silicon hoses? why cheap out and go to rubber? I guess typical OEM stuff....but problem solved. Always check vacuum lines in turbo motors, one leak could cause major problems.
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Your worst nightmare...
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As of this point I am opening a Paypal case for my 105 dollars. If he offers to sell you something beware, you have been warned.
I will post this in every single forum if i have to and report it to the moderators.
As of this point I am opening a Paypal case for my 105 dollars. If he offers to sell you something beware, you have been warned.
