NEED HELP!! vibration when dropping RPM

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02-26-2018, 11:08 PM

linkzk

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NEED HELP!! vibration when dropping RPM

Hi everyone,

Please help me.

My Q50 with VQ37 has vibration problem. I did a lot of search but nothing found.

I stop the car and move shift to P. I accelerate the RPM to 3000 and then release the gas pedal to let the RPM drop. This vibration happens at 1500 RPM and then gone.

This vibration happens only when the car is idling. This vibration happens only when RPM is 1500. This vibration happens only when RPM is dropping from higher to 1500. No vibration when RPM accelerates from lower to 1500.

I know this is G37 forums but the engine is the same.

Can anyone give me ideas about this problem? I went to dealer and they said this is normal. I really don't think this is normal.

Thanks.

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02-26-2018, 11:09 PM

JSolo

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It's not healthy to free rev the engine without load.

Last edited by JSolo; 02-26-2018 at 11:38 PM. Reason: Spelling!@#

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02-26-2018, 11:13 PM

linkzk

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Quote:

Originally Posted by Jsolo

It's not healthy to free rev the engine without loud.

Hi Jsolo,
Thanks for your reply. This is a mere coincidence. I accidentally pushed the gas pedal and noticed this problem.

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07-27-2018, 05:41 PM

johnnychobani

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I have the same problem. I guess it’s normal? 🤔

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07-27-2018, 06:45 PM

slartibartfast

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No-load revving to redline is not recommended, otherwise, don't worry about it.

When you say vibration, do you mean An individual part (i.e. heat shield) vibrates or do you mean the engine/transmission vibrates?

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07-27-2018, 09:55 PM

johnnychobani

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No, not to redline. Just revving pass 1500rpm, let's say 3000 and let it the rpm drop. It will hesitate/shake( it feels like the cars about to stall out) at around 1500 and then back to idling normally. Prob just need an idle relearn? I did cleaned out the TB and installed a CAI about two weeks ago. I also read that it could be the oil on the filter messing with the map sensor? Hmm who knows...

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