[oogabooga]

My car was misfiring like crazy so I took it in to the dealership since I don't have a cable to read the codes. Dealership replaced all the spark plugs and one of the ignition coils and the problem with the car shaking like crazy and sounding like a motorbike has gone away.

However, my car now idles at 750rpm as opposed to 600. No matter how long I drive the thing with the air conditioning off, the engine always settles down to about 750rpm. I don't think its the gas (I am running Shell VPower from the same station that I always go to). I've got 55k miles on the clock. I've used Techron Concentrate and that didn't help.

Anybody know what could be the cause? I've read that it could be injectors, VANOS, etc. I had one of the VANOS solenoids replaced about 700 miles ago and that temporarily fixed the issue. It is now back again. I will be replacing the vacuum hoses on my car very soon. I will be getting a walnut blast but don't think that it will solve the issue.

Thanks everyone.

[oogabooga]

Oh, also - I am stock AF. So problem won't be related to a piggy back, etc.

[oogabooga]

Anyone? I've ran 2 tanks of gas through the car and the problem still persists. Sometimes the car will come back down to 600rpm immediately like it should. But after about 10 seconds it shoots back up to 750rpm and stays there. I can also feel the engine make a thud when the rpms are fluctuating. Its really starting to annoy me :/

[kfrazie1]

Try resetting adaptions with a bav tech tool, Cobb, proceed, jb4, or Oft. This fixed my issue.

[BashShah]

Originally Posted by kfrazie1

Try resetting adaptions with a bav tech tool, Cobb, proceed, jb4, or Oft. This fixed my issue.

1+
Also.

Change all the coils.
How many K?
When is the last time you did a walnut blast.

Run 2 tanks back to back with BG44k in the tank or Chevon Techron concentrate. This is for injector cleaning not intake port cleaning.

Vanos, clean them.... It's easy and a few people have some good DIY on it here.

DN

[oogabooga]

53K miles on the car. I am due for a walnut blast as I haven't had it done yet. I'll run the injector cleaner through today and look into the vanos DIY and getting the throttle adaptation reset as discussed above also. Thank you!

[GoRomeo]

HPFP most likely...

[BashShah]

Originally Posted by oogabooga

53K miles on the car. I am due for a walnut blast as I haven't had it done yet. I'll run the injector cleaner through today and look into the vanos DIY and getting the throttle adaptation reset as discussed above also. Thank you!

Get the walnut blast done first.
Believe me, it is something that must be done, and it's symptoms are everything else you have to do anyways.

DN

[oogabooga]

So my car finally threw a reduced power warning and I took it into the dealer.... They said it was the vanos solenoids and third party warranty won't pay for them to be replaced. Looks like I'll be attempting the DIY. I think I also have to replace my camshaft sensor also. Anyone think that these two issues were causing my car to idle at 750 consistently or is there yet another problem?... Dealer also reset throttle adaptation which they told me resets the way that the car has learned about my driving... That didn't solve the issue.

[oogabooga]

Nevermind, my apologies. Dark nemesis did suggest cleaning the vanos solenoids. Didn't see that part of his message. Hopefully this solves it.

[BashShah]

Originally Posted by oogabooga

Nevermind, my apologies. Dark nemesis did suggest cleaning the vanos solenoids. Didn't see that part of his message. Hopefully this solves it.

I replaced mine.
Didn't help..... I think.

Had a walnut blast done.... This did it.
Then still had a slight miss fire so...
I changed my plugs and could at the same time and the vanos.
I was new with this car so I just wanted the issue corrected.

For you here is my recommendation:

1. Walnut blast.
2. Change all plugs and coils.
3. Change or clean both vanos Solenoids. And swap them.
4. Do a full adaptation reset.

Look for eBay seller: germanautosupply
His stuff is up to date and I liked it... Not to mention a really good price for the coils and plugs.

Spark plug tool from BMS.
Torque wrench from harbor freight tools. Set it to 20, not 23. No need for any anti-seize.... Which will increase the torque required.

Look for eBay seller: bmwofmin.
This is a BMW dealer.
Picked up the Solenoids for 105 each..... I called them....hehehe.

Invest in USB to OBDII cable and diagnostic software on your laptop.
It will help you for a long time.

BMWlogger software fee version do adaption reset and battery registry..... Along with other stuff.

The software I have is old, but it is BMW called DIS.

After all this: I ran 2 tanks back to back with shell v-power and 1 can of BG44k in each tank.
2 year later, no problems.

Recently I added techron concentrate to 2 tanks to try.
Works I think.

If it is none of the above, then at least your cars preventative maintenance is done.

Major difference is the walnut blast..... Day and night difference.
It was driving a different car.

DN

[oogabooga]

Originally Posted by DarkNemesis

I replaced mine.
Didn't help..... I think.
Had a walnut blast done.... This did it.
Then still had a slight miss fire so...
I changed my plugs and could at the same time and the vanos.
I was new with this car so I just wanted the issue corrected.
For you here is my recommendation:
1. Walnut blast.
2. Change all plugs and coils.
3. Change or clean both vanos Solenoids. And swap them.
4. Do a full adaptation reset.
Look for eBay seller: germanautosupply
His stuff is up to date and I liked it... Not to mention a really good price for the coils and plugs.
Spark plug tool from BMS.
Torque wrench from harbor freight tools. Set it to 20, not 23. No need for any anti-seize.... Which will increase the torque required.
Look for eBay seller: bmwofmin.
This is a BMW dealer.
Picked up the Solenoids for 105 each..... I called them....hehehe.
Invest in USB to OBDII cable and diagnostic software on your laptop.
It will help you for a long time.
BMWlogger software fee version do adaption reset and battery registry..... Along with other stuff.
The software I have is old, but it is BMW called DIS.
After all this: I ran 2 tanks back to back with shell v-power and 1 can of BG44k in each tank.
2 year later, no problems.
Recently I added techron concentrate to 2 tanks to try.
Works I think.
If it is none of the above, then at least your cars preventative maintenance is done.
Major difference is the walnut blast..... Day and night difference.
It was driving a different car.

DN

Thanks DarkNemisis. I was afraid that it was going to be walnut blast related as thats just out of my budget for the next few months. I got the 2A82 intake vanos solenoid code. I am going to try cleaning it out according to the DIY but I definitely agree with you - I think I am going to have to get a carbon cleaning in order to fix a lot of the weird symptoms i've been experiencing lately. Car is stumbling like crazy and lately its been idling at 900-1000rpm :/ I am definitely going to look into getting the diagnostic software you mentioned. I am sick of having to take my car in to figure out whats wrong with it

[oogabooga]

I am going to get the walnut blast done as DarkNemisis has suggested because I definitely agree with his suggestion that it will have the biggest impact on the car. I just don't understand why this issue only came up immediately after I had the plugs and one coil changed at the dealer after my car was misfiring like crazy.
So here is an account of everything that has happened:
1. Car misfiring
2. Took car to dealer. Dealer changed one coil pack and apparently all plugs
3. Car idle constantly rises to 750rpm and stays there after it sits still for about 15 seconds.
4. Dealer reset the car's throttle memory or whatever. I told them to reset the throttle adaptation but I am not sure what they did to be honest.
5. Car still has same issue. Car threw a reduced power error
6. Dealer found 2A82 intake VANOS solenoid error
7. I cleaned solenoids and swapped positions
8. Car idle still rises to 750rpm and stays there.

I am not too familiar with cars but I know for sure that when the idle fluctuates, I can feel the engine thump - there is also a distinct noise that comes from the front of the car when the idle change occurs. (Might be misfiring?)

In general the car just sounds a bit off when it is idling - there is a rhythmic pulse that I can sense with the exhaust that I never experienced before when the car ran fine.

[BashShah]

Your car is an 08 N54 engine.
Why didn't the dealer check the intake ports?
Check the history of your vehicle from the dealer..... Was the walnut blast done?

Also check if in the past, if any injectors were replaced?
Tell the dealer, I want the full history report in my hand.

If they say no.... Just say...."excuse me, this is my car, I need to know its history."
Else go to another dealer.

As for walnut blast.
Phone every mechanic shop in your area, and ask if they have a borescope to check your intake ports.
They should be able to give you picture of your intake port.

Indy mechanic cause it's cheaper.
Then phone everyone to see who can do the walnut blast the cheapest, professionally.
Make sure to replace the intake port gasket rings.... Very cheap, and on eBay.

DN

[oogabooga]

Originally Posted by DarkNemesis

Your car is an 08 N54 engine.
Why didn't the dealer check the intake ports?
Check the history of your vehicle from the dealer..... Was the walnut blast done?

Also check if in the past, if any injectors were replaced?
Tell the dealer, I want the full history report in my hand.

If they say no.... Just say...."excuse me, this is my car, I need to know its history."
Else go to another dealer.

As for walnut blast.
Phone every mechanic shop in your area, and ask if they have a borescope to check your intake ports.
They should be able to give you picture of your intake port.

Indy mechanic cause it's cheaper.
Then phone everyone to see who can do the walnut blast the cheapest, professionally.
Make sure to replace the intake port gasket rings.... Very cheap, and on eBay.

DN

DarkNemisis, I took your advice and I listed everything not related to oil services, brake pads, lights, etc. below. Not sure what was done with the injectors given the information contained on the print out that the dealer gave me.

My car currently has 54,000 miles, bought it with 47,500 on it for reference -

47,444 miles - FULL Flow filter w/cont ele-oil line leak (Defect Code: 11420048UW)
47,444 miles - Fuel temperature sensor permanent malfunction (Defect code: 1353181UW)
46,593 miles - FULL Flow filter body leak (Defect Code: 11420048UW)
31,672 miles - Idling quality under all operating conditions uneven running (Defect code: 1032003500)
27,466 miles - N54 HPFP B13, 13, 10 (Defect code: 0013930100)
27,466 miles - N54 Injectors B13, 14, 10 (Defect code: 0013960100)
17,087 miles - Fuel injector fault code stored in diagnosis fault code memory, warning lamp on

As for the walnut blast, I found an outstanding shop in SoCal that I am going to go to (Offset Motorwerks). The dealer I took it to said that I was due for a carbon intake cleaning but I highly doubt they actually checked the intake ports. They just stated "Car has rough idling and other symptoms - Suggest carbon intake cleaning"

I almost forgot, in addition to the codes above, my car threw a LPFP error code, camshaft sensor code, and 28A2 vanos code recently. Unfortunately the codes were deleted before I could get them fixed and they apparently have not popped up again for whatever reason (I dont have a tuner that would automatically delete them, etc.). I cleaned and swapped the 2 vanos solenoids and that didnt do anything.

[BashShah]

46,953 and after worries me.
Before that looks like warranty and recall stuff..., you are fine there.
Did you buy from dealer?

If so, chances are they have record of what they corrected.... Be very nice and ask them.... Don't threaten them.

Wait...
First go to another dealer and tell them your story.... If they say or mention any state regulation on the dealer to disclose info.... Then...
As a last resort.... Mention it softly to the dealer you bought from.

Find out the follow....MUST.
1. What dealer or shop they took the car to to get it fixed.
2. What part or parts they fixed.... Part numbers would be great.
3. Where did they buy the parts.... This will tell us if they are aftermarket or not.

Once we know the above, then you know what the problem start is.

It just could be all for nothing... Even the dealer you bought from got duped by some shop... That did not consider a walnut blast before anything.... But let's know everything.

Also if these were in DCT memory, that means no one cleared them... Interesting.
Why not?

Keep me posted after the walnut blast.
PM sent.
Ohhh and you spelled my name wrong....lol

DN

[oogabooga]

Originally Posted by DarkNemesis

46,953 and after worries me.
Before that looks like warranty and recall stuff..., you are fine there.
Did you buy from dealer?

If so, chances are they have record of what they corrected.... Be very nice and ask them.... Don't threaten them.

Wait...
First go to another dealer and tell them your story.... If they say or mention any state regulation on the dealer to disclose info.... Then...
As a last resort.... Mention it softly to the dealer you bought from.

Find out the follow....MUST.
1. What dealer or shop they took the car to to get it fixed.
2. What part or parts they fixed.... Part numbers would be great.
3. Where did they buy the parts.... This will tell us if they are aftermarket or not.

Once we know the above, then you know what the problem start is.

It just could be all for nothing... Even the dealer you bought from got duped by some shop... That did not consider a walnut blast before anything.... But let's know everything.

Also if these were in DCT memory, that means no one cleared them... Interesting.
Why not?

Keep me posted after the walnut blast.
PM sent.
Ohhh and you spelled my name wrong....lol

DN

Bought the car as a CPO from a BMW dealer. It had about 2 months remaining on the CPO warranty.

Whats weird is that my car never had this issue with the idle prior to the coil and plugs being replaced by the dealer.

I am not sure what you mean by the DCT memory (car noob here)

[oogabooga]

Have to bring this back. 1 vanos was replaced about 600 miles ago and this seemed to have solved the issue. However, just recently the car will not drop below 750rpm again. I was experiencing what I think are misfires at 600rpm idle (I can feel the car thud and "knock"). Anyone have an idea what is going on? I am at 55k... probably due for a walnut blast.

This is really bothering me and I feel like replacing all coils, the other vanos and getting a walnut blast should solve the issue but I just don't want to throw money at a car that has already cost me a sh*t ton in repair bills.

[oogabooga]

bump. hoping someone has experienced this before and has easy fix

[Sgop335]

Havent read all the posts, but have you changed All vacuum lines?

Otherwise looks like a nut blast, wouldnt mess with coils yet. Mine has 60k miles no blast yet. Idles at 600. Seemed to surge at 50k but smoothed out when i changed all lines with silicone and did berryman induction cleaning.

[oogabooga]

Originally Posted by Sgop335

Havent read all the posts, but have you changed All vacuum lines?

Otherwise looks like a nut blast, wouldnt mess with coils yet. Mine has 60k miles no blast yet. Idles at 600. Seemed to surge at 50k but smoothed out when i changed all lines with silicone and did berryman induction cleaning.

I will replace the vacuum hoses very soon. I just received them today. Its clear that the car's DME is causing the engine rpm's to stabilize at 750rpm for some reason. The car does not stumble or anything, just goes right down to 750rpm and does not move from there. I am starting to think that the issue might be with timing, etc as opposed to getting a walnut blast...

[Sgop335]

If the car is happy at 750 and doesnt surge, then wouldnt worry about it. Changing vacuum lines is a good idea anyway, just dont break anything