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Discussion Starter #1
Parked my car in the garage for the winter but for the past month I've noticed when I turn on the car that the RPM on cold start will fluctuate up and down and the engine sounds like its gasping almost stalling. With a little rev it seems to stabilize and sit stead at around 1500 RPM on the cold start. Checked the codes and saw that its misfiring on all 10 cylinders. I also noticed that It gave me a low gas fault but unfortunately i wasn't sure if it was because I only had 1-2 gallons left in the tank as I wouldn't think it needing a fill up would throw a code. Spoke with my friend about this and he thought misfiring could be a few thinks starting from spark plugs, ignition coils (not sure if thats the same as coil packs) or possibly even the fuel pump needing to be replaced. I also did a search and with other BMW's people have said similar things regarding the fuel pump and possibly even the fuel sensor. Thought I would check in with you guys and see if anyones had similar issues. Just for reference im doubtful that its any of my mods but Im using BMC filters, decat headers with full akrapovic exhaust, and a pulley. Not sure what it could be but fortunately and unfortunately I will have to wait till the spring to have my extended warranty cover it at the dealer but thought I would get a head start.

Thanks for the help and sorry for the long post.
 

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Does it only misfire on idle, but clear up when you rev or stuttering all the way ?
 

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So to explain in a little more detail what happens is I start the car and the rpm’s fluctuate about 500rpm maybe more up and down pretty drastically on cold start. As soon as the car sits for about 20 seconds and gets a bit warm the fluctuating stops and on drives it feels and drives normally. It might be easier if I post a video so I’ll try to capture it tomorrow. Thanks for the help.
Does it only misfire on idle, but clear up when you rev or stuttering all the way ?
 

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How old is your fuel? Did you fill up with fresh fuel?

The impurities in the fuel settle at the bottom of the fuel tank and can cause such behavior when they get sucked up in the fuel system. This is why I never let the fuel level drop below the last quarter.

Try to fill up the tank with fresh fuel and also add a bottle of a good fuel system cleaner. Then blast it around for a while and see if it gets any better.
 

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Any codes? My 07 m6 was doing that. I was getting codes for the MAF sensors. I cleaned them and the codes have not come back. Worth a shot to clean them. Mine was only doing it on cold starts.

Sent from my SM-G860P using Tapatalk
 

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Discussion Starter #6 (Edited)
How old is your fuel? Did you fill up with fresh fuel?

The impurities in the fuel settle at the bottom of the fuel tank and can cause such behavior when they get sucked up in the fuel system. This is why I never let the fuel level drop below the last quarter.

Try to fill up the tank with fresh fuel and also add a bottle of a good fuel system cleaner. Then blast it around for a while and see if it gets any better.
Thanks Hasan, But the car has been filled up a few times since Ive had this issue. After clearing the codes the problem weirdly enough has gone Im considering changing out my spark plugs and possibly coil packs. I've had the engine replaced under warranty at 55k miles I'm at 68k miles but not sure if they used the same spark plugs or swapped them out with new ones same goes for the coil packs. I do know that the spark plugs were changed at 45k miles so if they weren't changed out Im assuming they need to be changed since thats about 23k miles if they used the same plugs with the new motor. I saw a post you made a while back regarding Okada coil packs. Any ideas where i could purchase them from? Also if you have any info on aftermarket spark plugs or should I stick with the OEM's. I wish Okada wasn't so damn expensive haha.

Any codes? My 07 m6 was doing that. I was getting codes for the MAF sensors. I cleaned them and the codes have not come back. Worth a shot to clean them. Mine was only doing it on cold starts.

Sent from my SM-G860P using Tapatalk

I didn't get any codes for maf sensors but either way it might not be a bad idea to clean them. Can you give me any tips on how to clean them properly with out damaging the sensors?
 

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Thanks Hasan, But the car has been filled up a few times since Ive had this issue. After clearing the codes the problem weirdly enough has gone Im considering changing out my spark plugs and possibly coil packs. I've had the engine replaced under warranty at 55k miles I'm at 68k miles but not sure if they used the same spark plugs or swapped them out with new ones same goes for the coil packs. I do know that the spark plugs were changed at 45k miles so if they weren't changed out Im assuming they need to be changed since thats about 23k miles if they used the same plugs with the new motor. I saw a post you made a while back regarding Okada coil packs. Any ideas where i could purchase them from? Also if you have any info on aftermarket spark plugs or should I stick with the OEM's. I wish Okada wasn't so damn expensive haha.




I didn't get any codes for maf sensors but either way it might not be a bad idea to clean them. Can you give me any tips on how to clean them properly with out damaging the sensors?
There is a diy for MAF on here some where if you search. When i get near a pc i can email it to you if you need. I bought MAF sensor cleaner at autozone which im sure is just relabled electronics cleaner. I just took both mine out and sprayed them down, let them dry, and reinstall.

Sent from my SM-G860P using Tapatalk
 
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richku1
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