[ky0u]

Hi all

Had a weird issue pop up on my n54 recently. I first noticed it on the highway travelling about 80mph. The car would start hiccuping almost like a misfire or similar. However no codes pop up. Since then I was able to recreate the issue consistantly under the same circumstances

To my knowledge, the car has never been walnut blasted, could this be a cause? Also wondering if it could be vanos related

Notes:
75-80mph @ steady throttle. This issue does not occur during accel and if I accelerate while it's happening, it goes away

Downshifting also makes the issue go away which makes me think its more RPM related than speed. (~2.5k rpm)

Plugs and coils recently changed (about 8k miles).

Vacuum lines and solenoids all replaced (about 8k miles)

There are no codes that appear. I did a scan with MHD as well as borrowing a friend's Snap On Solus scanner.

Vehicle gauges all appear normal with no out of place behavior (no overheats, etc)

[Bimmer_Bro]

Originally Posted by ky0u

Hi all

Had a weird issue pop up on my n54 recently. I first noticed it on the highway travelling about 80mph. The car would start hiccuping almost like a misfire or similar. However no codes pop up. Since then I was able to recreate the issue consistantly under the same circumstances

To my knowledge, the car has never been walnut blasted, could this be a cause? Also wondering if it could be vanos related

Notes:
75-80mph @ steady throttle. This issue does not occur during accel and if I accelerate while it's happening, it goes away

Downshifting also makes the issue go away which makes me think its more RPM related than speed. (~2.5k rpm)

Plugs and coils recently changed (about 8k miles).

Vacuum lines and solenoids all replaced (about 8k miles)

There are no codes that appear. I did a scan with MHD as well as borrowing a friend's Snap On Solus scanner.

Vehicle gauges all appear normal with no out of place behavior (no overheats, etc)

If you have MHD see what you fuel pumps are doing during the issue. The low pressure fuel pump should not be dipping below 60psi.
Needing a Walnut blast is possible but usually this causes high rpm misfires or poor idle.

[Silent9n54]

Originally Posted by ky0u

Hi all

Had a weird issue pop up on my n54 recently. I first noticed it on the highway travelling about 80mph. The car would start hiccuping almost like a misfire or similar. However no codes pop up. Since then I was able to recreate the issue consistantly under the same circumstances

To my knowledge, the car has never been walnut blasted, could this be a cause? Also wondering if it could be vanos related

Notes:
75-80mph @ steady throttle. This issue does not occur during accel and if I accelerate while it's happening, it goes away

Downshifting also makes the issue go away which makes me think its more RPM related than speed. (~2.5k rpm)

Plugs and coils recently changed (about 8k miles).

Vacuum lines and solenoids all replaced (about 8k miles)

There are no codes that appear. I did a scan with MHD as well as borrowing a friend's Snap On Solus scanner.

Vehicle gauges all appear normal with no out of place behavior (no overheats, etc)

Do a log and see if the boost overshoots the target at low rpm and if the throttle gets cut at the same time

im having a similar issue with my 535i and u can feel a stutter or hesitation in low rpms without ever triggering a code.

[ky0u]

Originally Posted by Bimmer_Bro

If you have MHD see what you fuel pumps are doing during the issue. The low pressure fuel pump should not be dipping below 60psi.
Needing a Walnut blast is possible but usually this causes high rpm misfires or poor idle.

Originally Posted by Silent11N54

Do a log and see if the boost overshoots the target at low rpm and if the throttle gets cut at the same time

im having a similar issue with my 535i and u can feel a stutter or hesitation in low rpms without ever triggering a code.

Great suggestions, I'll give these a try in the next day or so, thank you!

[Silent9n54]

Originally Posted by ky0u

Great suggestions, I'll give these a try in the next day or so, thank you!

did you ever figure out whats going on ?

[ky0u]

Originally Posted by Silent11N54

did you ever figure out whats going on ?

Nah I was super busy during the week, probably gonna take some time to do it today or tomorrow.

[ky0u]

Figured I'd update this so it doesn't turn into an unresolved thread if someone stumbles on it in the future

My issue turned out to be a bad VC gasket that was slowly deteriorating. About 2 weeks after initial problems appeared, I started to smell burning oil.
Immediately checked the VC to head seam and found oil had begun to drip onto heat shield.

It looks like a slow leak started near the spark plugs and eventually deteriorated enough at the outside edges where the oil found a surface it could burn on.

No codes thrown at any time for this one