[ChadE]

So I have 2008 328i, it has a very rough idle; shakes the whole car. Surges, and has low power. It is throwing codes for misfire on Cylinders 1,2,3. I have changed the plugs and coils on cylinders 1-2-3 with no luck. It also is intermittent in a way, after some extended driving it will clear up and drive normal and power and MPG will come back. However if you cut it off even berifly it goes back to its same ways.

I have also changed out the MAF even though there were no codes. No change.

I am out of ideas, any suggestions?

[Taskmaster]

Valvetronic sensor is probably fouled. Un plug it and see how the car runs.

[mlifxs]

Long story, but I'm convinced some of the new Bosch coils are very particular about how you seat them on the plug. Don't know if you're even using Bosch coils but maybe this will help(?)

I recently decided to go ahead and do a plug and coil change. I replaced Bosch Genuine coils with a mix of Bosch Genuine and Bosch OEM coils. They looked identical and the supplier said there would be no issue.

After changing everything out, car would start, run unbelievably rough, then die. Like you, I had misfires on 1-2-3. I tried moving the coils around, switching one or two old coils back to get some idea about what was going on. I managed to get all but one new coil working without misfire. The misfire error would follow the coil as I moved to other cylinders, so I concluded the supplier sent me a bad coil. So, I sent it back and they sent me another new coil.

Sure enough, the new replacement coil misfired as well, and the misfire followed the coil to another cylinder. I was ready to give up and simply live with one old coil in it's place when I decided to re-check the seating on the plug. Finally got it to work and no problems since.

The newer Bosch coils have what looks like a spring loaded contact with the plug. The old coils seem to have some form of friction connection to the plug. You might try seating and re-seating the coil.

For me, the coil had problems on 3 and 4. The valvetronic is between them and crowds them a bit, so perhaps the coil was not quite seated correctly.

[ChadE]

Originally Posted by TheAxiom

Valvetronic sensor is probably fouled. Un plug it and see how the car runs.

Tried that no change. Still runs awful.

Cleaned both VANOS Actuators also even though no code for them.

No Change.

[Taskmaster]

Originally Posted by ChadE

Tried that no change. Still runs awful.

Cleaned both VANOS Actuators also even though no code for them.

No Change.

Ran with the maf unplugged?

[ChadE]

Originally Posted by TheAxiom

Ran with the maf unplugged?

No change, have already tried replacing it also.

[Taskmaster]

I would swap the coils and plugs from 4-5-6 with 1-2-3. I don't think they are seated like mlifxs said.

[ChadE]

Originally Posted by TheAxiom

I would swap the coils and plugs from 4-5-6 with 1-2-3. I don't think they are seated like mlifxs said.

Still no luck, Im thinking vacuum leak maybe?

[Taskmaster]

Thats plausible too.

[ChadE]

Originally Posted by TheAxiom

Thats plausible too.

What about precat o2 sensor? I Know usually a misfire takes out the o2 sensor instead of other way around, but Im just trying to figure out what would cause a whole bank to go out. Since the bank one o2 sensor is cylinders 1-2-3?

[Taskmaster]

Originally Posted by ChadE

What about precat o2 sensor? I Know usually a misfire takes out the o2 sensor instead of other way around, but Im just trying to figure out what would cause a whole bank to go out. Since the bank one o2 sensor is cylinders 1-2-3?

Do you have a diagnostic tool/software?

[Michu]

Check vanos solenoids.
http://www.realoem.com/bmw/enUS/show...diagId=11_3736

[ChadE]

Alright, I reset adapations and the car ran great, drove great and idled good again.

After the reset it threw codes
2CFB - Throttle Valve Adapation Value
2D09 - Throttle Valve
2FA4 - Incorrect Data Record (this was here before the reset of adaption also)

Then on the third start it went back to doing the same thing, throwing codes for misfire on 1,2,3; surging and rough idle and still the 2FA4 code.

Any idea what is causing this? It seems to me to be some sort of computer issue since it ran great right after resetting but then went back to old ways. I am open to suggestions though...
?

[ChadE]

I reset them again today, ran great. Drove it about 30 miles, and let it sit and idle for 30-45 minutes. However at the end of the idling it stared surging between 500 and 1200 RPM at idle and throttle was unresponsive. I then got a code for the Exhaust Vanos. I cleared the code and the idle came back to normal.

Could that be my issue even though I have never seen that code before?

[Three_thirty_I]

I see you have cleaned the solenoids, have you tried swapping them around? Then see if the error moves to the suspect solenoid's new position. Also most people forget about the Check Valves which work in conjunction with these solenoids and filter the oil - the filtering holes are so small that it takes little for them to become blocked, and if there is even the slightest possibility of sludge or the onset of sludge I am sure that they would be affected.

The eccentric shaft sensor is another possibility, even if it does not have oil contamination it is still a sensor that can fail, and there won't necessarily be a stored error code. Valvetronic motors can also become faulty, but in most cases it is the sensor that fails or becomes faulty.

[ChadE]

Originally Posted by Three_thirty_I

I see you have cleaned the solenoids, have you tried swapping them around? Then see if the error moves to the suspect solenoid's new position. Also most people forget about the Check Valves which work in conjunction with these solenoids and filter the oil - the filtering holes are so small that it takes little for them to become blocked, and if there is even the slightest possibility of sludge or the onset of sludge I am sure that they would be affected.

The eccentric shaft sensor is another possibility, even if it does not have oil contamination it is still a sensor that can fail, and there won't necessarily be a stored error code. Valvetronic motors can also become faulty, but in most cases it is the sensor that fails or becomes faulty.

Today, I swapped the plugs on the o2 sensors (precat) since it looked like they were possiably crossed. However I got a code for Mismatched plugs, so obviously they were correct. But the car runs great when the plugs are swapped, what would that hint to? That the pre cat o2 for bank one is bad, (have seen the code a few times here and there) and bank 1 is the one that misfires when it does its misfiring issues as well.

Does anyone know what the values for the O2 sensors should be when the car is running?

[ChadE]

Alright, I changed the O2 sensor, and put in a new exhaust VANOS solenoid. Still getting misfires.

[Three_thirty_I]

That is very strange!!! And frustrating!!

[ChadE]

Originally Posted by Three_thirty_I

That is very strange!!! And frustrating!!

I have now swapped the intake vanos also. No luck.

[Three_thirty_I]

The fact that you have 3 cylinders on the same bank misfiring made sense that it could be an issue with that corresponding O2 sensor. As far as I can see, you've done everything logical to do already. Very strange!!

[Delusive]

I'm starting to get the same problem as the OP but mines misfires from cylinders 4-5-6, I installed the AA Headers just recently and it was fine till now. I've read what the OP did but nothing helped him, so i'm assuming it won't help my problem either. I'm guessing mines has a vacuum/exhaust leak causing this for me.

[andrey_gta]

has any progress been made? I'm getting symptoms of coilpack, but this thread is scaring me