Hi guys,I've been having this problem lately and have no idea what it is.
When I stop fast the engine RPM drops really hard and the engine wants to stall and then the RPM comes back to idle normal,it never stalled yet but it wants to. When it wants to stall it shakes violently for a second,any idea what it is. I'm about to bring it to the garage but don't want to get ripped off with bad diagnostics,help please,thanks

Michel

 

This happens to me sometimes - When I forget to shift disengage the clutch and shift to neutral. I'm assuming that's not your issue...

Edit: Although now that I think about it, if you have an automatic, and your torque converter isn't unlocking fast enough, that could cause it.

 

Could there be a vacuum leak in the power brake servo or its check valve?
You'd probably notice some increased pedal pressure needed when this happens, though.

 

I forgot to say that i have the auto trans. with steptronic and it's doing that especially when it's cold out. Today the weather was 6.5 celsius here which is about 53 degree farenheit and it didn't do it,seem to be worst when it's cold only outside but not that cold. Need more info before I bring it to the garage,thanks guys !