[james4321]

How smooth is your N55 when idle? Mine seems to be fine, but you can feel very slight hiccup when on traffic lights (even less when on P. When It is D can feel It a bit more). Nothing really bad, just wondering if all N55s have this behavior. It is different, much different when AC is on. I can feel the same thing, but few times harder. Rpms are like glued, doesnt move at all, steady. Spark plugs brand new. no other symptoms. Does it even worth to pay attention?
Drive this car 5years, but maybe before I was not focused on It. Because thousand miles ago I had a problem with missifre, so I changed the spark plugs. Thats why I try to catch if there is some misfire maybe, so I am more focused on It.
Car runs fine, has power, No misfire, No codes.

[thejeremyman9]

Idle should be smooth, shouldn't feel anything especially when in D. Could be any number of things...coils, MAF, etc. If no other symptoms probably not losing sleep over, just monitor and make sure it doesn't get worse.

[Jvac]

Originally Posted by thejeremyman9

Idle should be smooth, shouldn't feel anything especially when in D. Could be any number of things...coils, MAF, etc. If no other symptoms probably not losing sleep over, just monitor and make sure it doesn't get worse.

+1 n55 is the smoothest engine I've ever owned. Purrs like a kitten at 45000mi on original plugs and coils. But, as enthusiasts I think we pay a little too much attention to the most minor things. Running well and not throwing any fault codes? Leave it alone and stick to the scheduled maintenance plan. No sense throwing parts and money at a car trying to achieve perfection. These are mass - produced consumer cars, even though I like to think I'm special for owning one. There's bound to be some flaws that are not indicative of anything serious.

[SCS55]

Mine was smooth at idle until I replaced all 6 coils due to a misfire (bad #6 coil). Now it's incredibly smooth idling. Even with the AC on.
My 2c
2015 335i Msport
137,000 miles

[james4321]

Can It be caused by bad fuel quality?
Before I filled the tank with the fuel I have now, there were no problems at all.

[spiff56747]

Could be issues with Valvetronic, you should get a code eventually though and a check engine light.

[thejeremyman9]

Originally Posted by james4321

Can It be caused by bad fuel quality?
Before I filled the tank with the fuel I have now, there were no problems at all.

It would have to be pretty bad, and that would like cause problems under higher load as well

[james4321]

I have refilled the tank with the fuel I am sure is high quality. I am not sure, but seems to be better.
I think, you guys get my description like my car shakes a lot. :-) And It can be my bad.
It is VERY slight vibrations, like somebody would kick ‚gently’ my front tire. 😀 My gf is not even able to feel it. That’s what she says.
The biggest ‚issue’ is when you turn on AC during the stop and this ‚seat massage’ takes like 15sec and then is okay.

[COKen]

What did you use to pull the codes? If your code reader isn't designed to pull BMW codes you may be missing some codes from some modules.

Some codes don't show up on some readers unless they reach a certain threshold. With some issues the car will keep track of the number of times it happens, but won't trigger any lights until a certain level is reached.