[bender rodriguez]

Sometimes it does it on a cold start.. Sometimes it feels like it does it after running the car pretty hard.. It will shake for about 1 second the rpm will varry slightly. It is at random and my car doesn't throw any codes. It happens maybe once every time I drive if that.

[Sethism]

Yeah, I've noticed it as well. I have always attributed it to some component or pump switching on.

[bender rodriguez]

Originally Posted by Sethism

Yeah, I've noticed it as well. I have always attributed it to some component or pump switching on.

Has it always done it for you since you had the car? Did you buy it new

[Bmr3sn]

Mine did it for about a second or two the other day. It was on a cold start up, hasn't done it since then and had never done it in the couple of months I have owned it.

[Sethism]

Originally Posted by Mr.Ritz

Has it always done it for you since you had the car? Did you buy it new

I've only had the car for a month. Mine does it on cold start, and occasionally while stationary at a light. It doesn't feel like an unbalanced shaking or anything. Just a minor derivation of the idle, accompanied by a very mild vibration.

It's got to be a pump pulling vacuum.

[bender rodriguez]

Originally Posted by Sethism

I've only had the car for a month. Mine does it on cold start, and occasionally while stationary at a light. It doesn't feel like an unbalanced shaking or anything. Just a minor derivation of the idle, accompanied by a very mild vibration.

It's got to be a pump pulling vacuum.

Yeah that describes it pretty well.

[etraud]

yes, I get the same thing. I got a '09 328i. I noticed this after I changed the plugs. It all started one day with check engine light on and really bad shaking, it was a misfire code. I researched for solutions and the cheapest was change plugs and ignition coils...well, I changed only the 6 plugs and not the coils. I did the test and swap the ignition coils and it didn't seem that was the problem. the plugs were kind of burned up so I closed the case and assumed it just needed spark plugs changed.
Right after changing the plugs and pulled out of my garage, and stopped to put it in Drive, I noticed right away...there was a rattle/shake feel. The check engine light turned off after a day or so and it has been running smooth...except that rattle/shake for a second at traffic lights. I've noticed it it happens when I first drive the car in the morning and i get to the stop light. It does it for a second every 5-10 seconds. Rarely, it doesn't happen. Since there is no check engine light, I am not too concern but it doesn't feel right, it feels as if the car is about to turn off for a sec. but it doesn't.
I hope one of the experts points us in the right direction.

[Delusive]

I get it at cold start up all the time, it could be because I haven't changed my spark plugs yet but i'm at 74K and it doesn't throw any codes at all. From what I know this shaking/rattle can be any of these: bad spark plugs, bad ignition coil, fuel filter, dirty air filter, bad crankshaft sensor, and more.

But most common fix are spark plugs, ignition coil, and crankshaft sensor. Some people overlook replacing the fuel filter which should be replaced every 50K miles or 4 years.

[bender rodriguez]

Shouldn't all those problems throw codes?

[cisf0rcalvin]

When mine does that, I hit the brake a little harder and it goes away.

[Delusive]

Originally Posted by Mr.Ritz

Shouldn't all those problems throw codes?

Sometimes they don't throw any codes at all and then the next thing you know your car doesn't want to start up, it dies while being driven, or rough idle.

[bender rodriguez]

I am prob going to do my spark plugs soon... But I don't know about doing fuel filter before 100k

[Sethism]

Originally Posted by cisf0rcalvin

When mine does that, I hit the brake a little harder and it goes away.

I've noticed the same thing. Which would also draw from the engine vacuum. Pretty sure it's a pump or something.


Now if it's violent shaking or throws a CEL, that's different than what I'm talking about.