# RPM drop then bounce back up while in gear when I let off gas.Normal or not?



## Mohammad Abdulkhalik (Dec 19, 2019)

VioletandPink said:


> So I noticed today when I was driving home from town that when I let off the gas while cruising in M6(1.4/auto)with the A/C on and fan on full blast the rpm's will drop around 300 rpm a second or two after I stop pressing the pedal and then will bounce back all within a second,is this normal?I noticed that this doesn't happen as far as I can tell when the A/C and fan is off and I'm thinking that it's somehow DFCO related maybe because I believe that activates about 2 seconds after you release the pedal if I remember correctly.I don't normally drive with a/c on even on the hottest summer days so that's why I'm just noticing now.
> 
> Edit:When the rpm's drop and bounce back it does not cause any engine braking.


Hi
I am not sure if I am having the same issue but I noticed that too. especially at low speed when I let off the gas RPM drops fast below 800 then jumps up to 900 or 1000. When the car does this I feel the car is pulling down as if changing gear but it doesn't. once I was driving very slow and tun to the left side then suddenly engine shutdown and I am thinking its related to this issue.

Attached link to some videos I shot can show how RPM drops then jumps up.






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photos.app.goo.gl


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## jblackburn (Apr 14, 2012)

I think both of our current cars (VW with an Aisin and the Cruze with the 6T) do something similar at low speed - it's not actually shifting, but the torque converter acts like a clutch to smooth on/off power transitions so you don't feel a jolt/bump every time you touch or let off the throttle.


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