car starting shaking

[99bimmer]

hi everyone im new to this forum and had a question about my 99 323i. i got into my car turned it on everything was fine...i backed up realized i forgot somthing pulled back into my parking space and the car all of a sudden started shaking (it wasnt moving when it shoke) rpms didnt change. the car is a 5spd with about 74,000 miles on it. no warning lights came on and the car didnt stall. The car hadnt been driven for 2 days and when i took the car out it didnt shake anymore...could it just be cause the engine was cold or is there a more serious problem. this is the first time it has ever done this. Any ideas on what this is...

[EXtech]

Sounds to me like a vacuum leak. Most common causes on the E46 are the crankcase vent valve failing or the crank case vent hose is deteriorated and developing a leak. The other possibility is a loose intake hose but my money would be on the first two. The vent valve is not exactly a DYI piece and neither is the hose.

[99bimmer]

So i start my car today its been a day since i last posted this and now the rpms at idle are higher than they normally are...when driving everything is fine.At stop light the rpms seem to be fine just when u first start it up they are higher. One more thing at the stop lights is my miles per gallon gage goes from past 50 to around 30 then goes back to normal..im not in gear or reving the engine and the rpms dont change . im taking the car to shop on mon. to see what they say about everything....ill mention what u said...thanks for the response and if what i just said is all related to what has been happening let me know thanks again. by the way the car hasnt shoke any just that one time about 3 days ago.

[JimmyDreams]

Out here, when something like that happens, we think EARTHQUAKE first...


Good luck! Let us know when the mechanic says in case this happenes to one of us!

JimmyDreams

[daenosx]

Im having the exact same problem......let me know what the mechanic says and how much it was to fix it? If you dont mind.

DAENOSX ghead

[99bimmer]

ok well i thought i could go today (mon.) but have to wait all booked up so my next days off work are thurs and fri ill let u know then later...cars driveable but still want to make car as perfect as i can later....Ben

[99bimmer]

well i took the car to the shop i started the car with him in it and showed how the rpms hang around 900 but thats when the car is cold then as the temp goes up in the car to normal the rpms go to around 600-700 and he said thats not really that bad but to put in BG 44k advanced formula in my car to clean my fuel system since the car has 74k miles and prob. has alot of carbon build up this should fix my rpms at idle from being wierd sometimes.he says i dont have a vacum leak if i did he says rpms would bounch all the time..he didnt mention anything about the crank case but i forgot to ask...he says everything else loooks fine..as for the miles per gallon gage he said that the sensor for it is proberly going and dont waste ur money till it breaks since it wroks when driving jsut when in neutral coming to a stop it moves like that(rpms at lights are good jsut the start up). has anyone every used that product in there car and how has it worked for you.the can says safe for all fuel systems... and he even told me that mercades (bmw is better) uses it alot to help keep down cardon and other deposits in there engines...so i guess ill give it a try and see how it does...what does everyone think????? the price to fix a full tank of gas so i can put the product in which now a days is like $100...Later Ben...o and no labor

[Bimm]

Hi! I started to have the same problem but it doesnt last, does it have to do with the type of fuel? I've used prem. fuel ever since i've owned the car, sometimes i wonder if its worth it esp. with how expensive gas is! Let me know if it works in your car!