SMG engages clutch when decelerating at high speeds, rpm drops until engine dies

[sebastian bmw]

Hey guys I've recently encountered this issue. Yesterday while driving on the highway my car suddenly began to drop RPMs as if the clutch would engage every time I would ease off the throttle... Trying to understand what was going on, I was messing with my throttle while driving, repeated easing off the throttle, changing gears and it would occur on any gear... if I gave it throttle again the gear would be re-engaged and I could accelerate again... I let the RPMs drop all the way, expecting it to remain and idle and the car just turned off... turned it back on and the car had the same issue all the way until I got home...

While driving today, the car drove just fine but did drop RMPs once and turned off on me when I eased off the throttle on the highway. I didn't even notice it happen as I was just slowing down a bit. This only happened once today and the car drove fine after, getting me through the day with no issues. I've researched online trying to find someone with the same issues and haven't been able to find a reason for this to happen. Any help would be great!

I got a tire puncture the morning before this happened, tire pressure light has been on ever since as I am driving with a spare wheel while I wait for a new tire to ship in. I doubt this would relate to my problem.. what do you think?

Thanks!

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BTW I have an 04 M3 SMG with 103k miles

[GeorgeF31]

The clutch should always be engaged unless you are in neutral, stopped, or between shifts. If you can be in any gear and have the engine drop RPM until it dies/stalls, the clutch is probably not engaged when the engine does -- you'd also feel the standard clutch-stall lurch. You may have an issue with the SMG, but if taking your foot off the accelerator causes the engine to drop down until it dies, that's a whole extra problem. The SMG may be acting strangely because of whatever is causing that issue with your engine.

If you just brake without downshifting, does the transmission automatically downshift? When the stall occurs, do you get a lurch from the car in first gear or does the engine just die?

[jibbajabba]

Bringing this thread back from the dead.

Same issue. Decelerate and the clutch engages dropping rpm to idle until you just touch the throttle and it whips back up to where it should be. Also, will randomly engage clutch and rpms rise until you release the accelerator. All gear sensors don't show it going into N, no fault codes at all, clutch and flywheel are good, new clutch slave, new gear position switch, swapped SMG brain.

Anyone come across this one before?