Subtle Jerks When Idling
 

Hey Everyone,

I'm experiencing a strange little issue that seems to have been happening as of late and I wanted to see if I could use the collective wisdom of NAM before heading over to the dealer.

After I've been driving the car for a while (about 20-30 mins+), whenever I am stopped for a bit the car will experience some subtle rhythmic jerks every 2 or 3 seconds. It's not something I've ever noticed before and it's only when I'm stopped in drive. If I go to park, or even turn on sport more, I don't notice the jerks at all.

Another interesting note is that if I drive it a bit aggressively, the jerks are a little rougher. I'm hesitant to take it to the dealer because I know they won't be able to "replicate the issue" as it only happens after a long drive.

I have a 2011 MCS 26K, no mods yet.

Any one else experiencing this?

Torque converter trouble maybe?

What does your tranny fluid look like? Topped up? Recently replaced?

E

If you cycle back and forth from Sport to Normal while the hesitations are occurring, do they come back and go away with each cycle?
E

That's actually a tricky question to answer. The jerks occur for about 10 seconds when stopped. After that, it idles normal. If I cycle from Sport to Normal during that time, the hesitations continue. If I'm stopped and the hesitations have faded, cycling to Sport and back will not make them occur again.

EDIT: Just tried again today and the jerks DID COME BACK after cycling through sport and normal. I'm stumped...

Seems like it's a bit difficult to check, but I haven't topped it off or replaced it yet as I'm only at 26k.

Tranny fluid is very difficult to check for both manual and auto. Not sure which one you have. Both are supposedly lifetime fluid. I would try to rule out other things before proceeding there.

Mine always has a rougher 4 cylinder type idle that is normal.

Hmmm... Didn't know BMW had made the Autos as hard to check as the manuals... It used to be a good indicator of transmission health.
(Another compromise due to size constraints, or a Bimmer thing?)
What drew me to the post was the hesitations - mine has been doing so since very new from about 35C to 60C coolant temp. As the engine slows to idle, it sputters a bit a few times then settles. That takes about 10 seconds... I hadn't tried playing with the Sport button, but will next time I'm out...
E

So... Dunno if this will help Fox718 out...

Took my MCS in for its first free oil change - they also carried out the coolant temp sensor replacement recall.

While my problems were at colder engine temps, they followed similar patterns to Fox718s'. Stumbles and hiccups that stabilise after 10s or so...

They're gone now.

I still have a sluggish thermostat to deal with - for another post...

Do you now if the recall was carried out Fox718?
E

Well, I had a thermostat issue that was settled before the recall was carried out. I'm not entirely sure if my issue was the same as the one in the recall but I was told my car wasn't part of the recall.

I'm up for an oil change in a couple thousand miles so I'll ask them at that point unless it gets worst.

Looks like it'll remain unresolved for now.