[xanman72]

I just got my 100k maintenance on my car done, this included spark plugs.

I've noticed when merging on the highway at full throttle (2nd gear) at about 5000 rpms the throttle will stutter, keep accelerating, then stutter again. This doesn't happen in higher gears. Any ideas what the issue could be?

After doing some initial research I think coil packs could be a possibility, but I could be totally off.

[tlow98]

You’re probably right about the cool packs, but a code will be stored in your ECU regarding the issue.

Either read the codes or have them read and move on accordingly from there.

[gbalthrop]

Originally Posted by xanman72

I just got my 100k maintenance on my car done, this included spark plugs. I've noticed when merging on the highway at full throttle (2nd gear) at about 5000 rpms the throttle will stutter, keep accelerating, then stutter again. This doesn't happen in higher gears...

QUESTIONS:
1) Do you know what brand/part# plugs were installed, and what GAP was set?
2) Does the SES light come on when this "Stutter" occurs?
2a) Does the engine run rough for 30 to 60 seconds after the "Stutter" occurs and then return to normal, and/or the SES goes off after such time?
3) BEFORE the plug change, did anything similar occur?
4) What else was done in the "100k maintenance"?
5) I assume what you are describing that occurs SINCE the plug change ONLY occurs at ~ 5,000 RPM and above?
6) Do you have a scan tool, even a generic P-code reader, that can scan for "misfire" faults (P0301 through P0306)?

Without knowing what fault codes are saved in DME memory, we can only guess as to the cause, but generally, "misfire" at high RPM and load suggests the coils or plugs are unable to provide spark of sufficient voltage to ignite the fuel as they have to fire >40 times per second. That could be due to one or more coils being bad, OR it could simply be a plug issue, such as gap too large (should have been gapped to .040").

Such a "misfire" would cause the SES light to come on, and likely cause very rough running for 30 seconds or more, so that does NOT fit your description if your "Stutter" is just momentary hesitation, which is more consistent with fuel delivery, or something else that affects ALL cylinders equally. I see you are in CA -- if you have an N51 engine (SULEV) then the extended SULEV warranty may cover some Fuel System/ pump issues. A fuel pump speed deviation test (Activation of Pump using INPA/ISTA) might be in order.

George

[Jesda]

Replace all of the coil packs now.

You could do one at a time but you'll end up doing them all within a year or so anyway.

[tlow98]

Originally Posted by Jesda

Replace all of the coil packs now.

You could do one at a time but you'll end up doing them all within a year or so anyway.

Not true. There is a huge variation in life with the coils.

I’d say it depends more on how handy you are than anything

[xanman72]

2. SES light does not come on.
2.a. The engine does not seem to run rough after the momentary stutters
3. No before the plug change the stuttering did not occur
4. Other maintenance Items were oil, oil filter, transmission fluid, oil
5. Yes this occurs at 5k+ RPMS
6. My mechanic gave me a printout of codes that were being thrown.

Dynamic Stability Control (DSC) (dsc_87 5E19 - Engine Management interface).

[xanman72]

If I continue to drive the car will this cause any more serious damage?

I have a N52 engine, 2008 328i, is there an expected lifecycle for the coil packs?

[gbalthrop]

Originally Posted by xanman72

2. SES light does not come on.
2.a. The engine does not seem to run rough after the momentary stutters...
6. My mechanic gave me a printout of codes that were being thrown.
Dynamic Stability Control (DSC) (dsc_87 5E19 - Engine Management interface)....If I continue to drive the car will this cause any more serious damage? I have a N52 engine, 2008 328i, is there an expected lifecycle for the coil packs?

If you had a "misfire" the SES light would come on and a "Misfire" fault code (P0301, P0302, etc. thru P0306 would be saved in the DME memory. You have NONE of those things. A "misfire" is any event which causes one cylinder to have LESS power developed during its power-stroke than the cylinder immediately before or after it in the firing order.

It is detected by a very momentary slowing of crankshaft RPM during the "misfiring" cylinder's power-stroke, as detected by the Crankshaft Position Sensor. A bad plug, bad coil, bad fuel injector, or anything in the power supply or activation circuit of a coil or injector can cause a "misfire" as defined by this system.

Anything that affects ALL cylinders equally, such as a momentary cessation of function of ALL fuel injectors, or ALL coils, or a momentary loss of fuel pressure at the fuel rail, would cause a "stumble" or cessation of power in ALL cylinders for that brief interval, and NOT set a "misfire" code or light the SES light.

My interpretation of the BMW FC you list suggests a bad electrical connection at the DSC Connector or the DME Connector, related to the PT CAN Bus or PowerTrain "network cable" that connects the various modules as shown in this TIS circuit diagram for the "Powertrain CAN bus":
https://www.newtis.info/tisv2/a/en/e90-328i-lim/hAR8BYR

Your list of jobs performed at the time the plugs were changed does NOT suggest any reason why the connector that includes the PT CAN Bus, either at the DSC or the DME should have been touched.

You might ask your mechanic/tech if he know of any way to test continuity of the PT CAN Bus, or might have done anything to affect a wire or connector related to that BUS. Also, if there is ANY chance that wheel slip occurs when you feel the "stutter" read the function of DSC & DTC.

As others have suggested, coils don't have an "expiration date."
Also, there is NOTHING in what you describe, including the fault code your mechanic provided, that suggests ANY damage to anything by continuing to drive the vehicle as is. If there is any cause for safety concern due to stumble or hesitation, that would be the only reason I can see to feel the need to immediately diagnose the fault & correct the issue.

If it is just a minor aggravation, it probably is more trouble or expense to try to diagnose now. I'm a DIY type, and I would just CLEAR any existing code after recording ALL relevant information including Freeze Frame Data, and drive the vehicle, occasionally enjoying WOT acceleration in 1st & 2nd to ~6,000 RPM to see if the condition continues, and NOTE/ Record the mileage on any occasion the "stutter" occurs. Then after it occurs recheck Fault Codes and Freeze Frame Data (mileage & engine conditions at moment code was saved, along with number of occurrences of fault).

Please let us know what you find,
George

[xanman72]

While commuting home from work today I noticed it only happens in 2nd gear. Not sure if this means it is a transmission issue or the engine is increasing speed the fastest to where this stuttering is noticeable.

Would like to know if anyone else has encountered this issue. Could it be a fuel pump or transmission issue?

Also, looking into PT CAN Bus connectivity and will try and troubleshoot.

[gbalthrop]

Originally Posted by xanman72

While commuting home from work today I noticed it only happens in 2nd gear. Not sure if this means it is a transmission issue or the engine is increasing speed the fastest to where this stuttering is noticeable...

If it does NOT "stutter" in 1st taking it to 6,000 RPM before shifting to 2nd (WOT), it stutters in 2nd, but NOT in any higher gear (have to be careful where you try that in 3rd & higher ;-) that DOES suggest a transmission issue. When this has occurred in the past, are you using (1) "Steptronic" or Manual shift, (2) are you in regular "D" gear selector position, or (3) are you using M/S with automatic shift in Sport Mode? Most people who have M/T state that in their vehicle description, so if I have falsely ASSumed you have A/T rather than M/T, please advise.

Depending upon Selector position as a variable, it is possible that you have "early onset" of wiring harness breaks in the shift lever wiring.

I would have a little more fun testing it to redline in all three gear selector positions. If you are using M1 to 6,000 and it doesn't stutter, I can't think of any reason OTHER than something connected to transmission electronics where it would do it ONLY in M2.

If the stutter is like a false or aborted attempt to upshift, or a ragged upshift, then maybe you've narrowed the search. Are you SURE that there is NO communication fault in the EGS (Transmission Control Module)?

George