rough idle...

[liquidtiger720]

This morning it was about 45* F. Maybe a degree or two colder then most days, but it wasn't cold at all (I am in San Francisco). I started my car, and almost immediately felt something odd. The whole car was shaking, like somebody was bouncing up and down in the passenger seat. I opened up the hood, and saw the whole engine shaking violently.Because of this, I decided to drive a different car to school. Anyways, I got back home, started it...the shaking thing happened again, then it smoothed out as it warmed up a little.

Is this violent shaking anything to be concerned of?
Could my oil weight have something to do with it? (i have castrol gtx 20w50 in there).

Any opinions about this would be appreciated.

[632 Regal]

thick oil does take more power to pump the oil, might be enough to have an adverse effect but I would check further into intake leaks and basic stuff like that.

[digitaldragon03]

I get the rough idle in the mornings. It usually goes away after driving for 10 minutes. Never gets rough if i start it in the afternoon though.

I think my car just doesnt like mornings. It idles rough, and it also doesnt want to lock the front passenger door when i try to lock it with my key on the drivers side. But in the afternoons and nights, everything works just fine, even if i hadnt driven it all day.

[liquidtiger720]

thick oil does take more power to pump the oil, might be enough to have an adverse effect but I would check further into intake leaks and basic stuff like that.


I know its a beaten horse...but would m1 0w40 be too thin for summer temperatures? (anywhere from 40* -110* F)

[ryan roopnarine]

nah, the oil has nothing to do with it. i changed my oil to 15w40 delo, which is a heavy duty diesel oil, a couple o' days ago. it was 40 in the morning and i had to drive to court....was making some undesirable noises, but was understandable. went back in to get my forgotten brief holder and a digital camera, thought it was gonna be finished, wasn't. i have the same engine as you....and have to say that you're suffering from a vacuum leak somewhere. my icv would do the same thing if the line was restricted, which is almost unlikely if you are using the bmw part icv line. shaking happened with restrictions, high idle with leaks....you likely have a leak that you need to find. the shaking at idle is fun, no? you have to put some gas into it to keep from being embarassed at the lights.

[Qube]

I get some shakes at low RPM in 3rd in the morning... but that's it. And that's only in the morning and the first time I shift into third low rev. You say 'violently' so I would definitely think there is a problem. If you have to use the word violent, then you yourself feel there is a significant problem anyhow! :)

[liquidtiger720]

You know what, I remember now. I should go check it. The hose that goes from the ICV to the intake was cracked, or the nipple that comes out of the intake and connects to the hose. I remember using a clamp to fix it. Funny, when i found this leak, it fixed weird rpm drops between 2k rpm and 3k rpm. Thank you guys for helping me out. I appreciate everybody, every one of you.


Edit: did i mention that after the car warmed up, the car drives normal with no rough idle?

[digitaldragon03]

Haha, ryan is right. It is embarassing at times, have to shift it into neutral and give it some gas to get the rpm up. Never know when a lady might see you in your shakey bimmer.