Misfire Cylinder

[Siavash]

Hi All
I am new in this forum. I bought a 2002 320i BMW with 200K on it last month. After few days I realized that the car was shaking when I started it off and the light engine came on. I showed it to our local BMW. They found a misfire on cylinder # 6 along with a fault on the mass airflow sensor. They changed the coil on cylinder #6. After one day, it happened again. I showed it to another mechanics (BMW Specialists!) and he changed all six spark plugs but the problem did not go away. I have spent about $700 so far and I do not really want to spend more (I would buy a new one if I wanted to spend more!). It usually happens in idle condition when the rpm comes down from 1200 to 600 and when I just start the car in the morning. If I turn off the car or when the car gets warm, the problem usually goes away. I also found that if I push the accelerator for about 1-2 minutes, it does not shake. The light engine comes on and off intermittently. Moreover, I feel sometimes hesitation in low gears. One of my friends suggested me to shift from premium to mid-grade gas. I might try that nest time. All your comments and helps are greatly appreciated.

[sonspot]

spark plugs was a good start, you could have them yourself, save a lot money, check the intake boots for cracks, really look at the lower intake boot, the small arm usually cracks, you have to feel it not just look at it,.

all e46 have a vanos problem the seals dry out, symptoms are cold start, low power below 3000 rpm, you dont need to change the vanos, unit just the seals.

your car was design for premium fuel, why would someone say use lower octane?..

read these

Beisan Systems - Procedures - Double Vanos Procedure

Vanos seals solution - E46Fanatics

thanks

[Siavash]

Thanks a lot for the comment and link.