[be-em-veh-808]

Not sure if this is best place to post this or if it's a DYI section, but here it goes ...

I changed the spark plugs in my 2007 E91 this past weekend.

All went well/smoothly. I assumed that the spark plugs (NKG --- for N52 engines per realoem.com) came 'pre-gapped". Also noticed the packaging/box indicating not to change the gap. So, I didn't check/adjust gap.

After putting everything back in place, I started the car and noticed that there's an extra rumble/shake that transmits to the footwell and transmission tunnel areas.

It is a very noticeable difference. 100% sure it was not there before. The shake is definitely felt and the extra rumble is definitely heard.

Idle is fine --- upon cold start --- 1000-1100 RPM for first 30 sec --- then down to 600-700. Drives fine on the freeway --- put in over 200 miles with no issues. No warning lights appear.

I'm a bit worried about the rumble/shake --- something just does not seem right. This is especially apparent in the first engine start of the day. Turning engine off also triggers this engine rumble/shake --- though less severe.

Any ideas what's going on? Should I remove all plugs and verify gap? Are plugs over/under torqued? Ignition coil need replacing? Please advise.

Thanks!

[F80_M3llow]

dont worry bro its normal i have changed plugs twice on my 06 325i and i get a rumble. Dont worry all ood

[MaximusJ]

Its normal; for now.

Did you reset the adaptations? I did and the shaking was gone after +/- 250-300 miles.

Its supposed to go off with time; if not, check the gap.

[be-em-veh-808]

Fanantic ---

Thanks for chiming in with your experience. I'll TRY to stop my worrying.

Originally Posted by BMWE90FANATIC

dont worry bro its normal i have changed plugs twice on my 06 325i and i get a rumble. Dont worry all ood

[be-em-veh-808]

Maximus ---

Thanks for replying. I don't even know what it means to 'reset adaptations' --- so, I guess I did not reset the adaptations.

Can you kindly explain?

I've driven about 200 miles so far. So, will keep monitoring.

Thanks!

Originally Posted by MaximusJ

Its normal; for now.

Did you reset the adaptations? I did and the shaking was gone after +/- 250-300 miles.

Its supposed to go off with time; if not, check the gap.

[RazRokz.!]

Same thing happened when i changed mine. After 100-200 miles it gradually goes away.

[N0OS3]

about resetting your adaptions, i think is meant to reset the monitors in your dashboard. To reset do the following:

1. Put your car in AC mode. (click the key in)
2. Press the start key ONLY (do not hold the brake)
3. Press and hold the ODOMETER button on the dashboard until all other warnings have cycled through (if you have any). Use the scroll button [that usually increases or decreases cruise sensitivity] to cycle to the spark plug symbol.
4. Hold the selector button [the button on the cruise control knob] on that symbol until it resets or asks you to reset. Just hit the selector button and it should clear out and reset your service timer to 65k miles or something like that.

**If you have a tough time understanding these instructions, just dig through your owner's manual and it should have it in picture form in there.

[MaximusJ]

Originally Posted by lync9763

about resetting your adaptions, i think is meant to reset the monitors in your dashboard. To reset do the following:

1. Put your car in AC mode. (click the key in)
2. Press the start key ONLY (do not hold the brake)
3. Press and hold the ODOMETER button on the dashboard until all other warnings have cycled through (if you have any). Use the scroll button [that usually increases or decreases cruise sensitivity] to cycle to the spark plug symbol.
4. Hold the selector button [the button on the cruise control knob] on that symbol until it resets or asks you to reset. Just hit the selector button and it should clear out and reset your service timer to 65k miles or something like that.

**If you have a tough time understanding these instructions, just dig through your owner's manual and it should have it in picture form in there.

That's just the service timer. Its only to reset the counter to re change your plugs in 60k miles.

By adaptations, I mean basically "reset" the ECU; like you never drove the car before. It will then adapt to the new spark that the new plugs gives, but it always shake a little.

I reset my adaptations as soon as I change something on the car; even the wheels. I do that with my Bavarian Technic cable. Most shops that works on bimmers can do it for a small fee too.

Its not mandatory, but when you mod a car, you can see results instantly. The car still need to adapt a bit to your new components, but while doing so, it makes the adaptation a lot easier.

Hope it helps!

[be-em-veh-808]

Maximus / BMWE90Fanatic ---

Both were right on the money. The rumble/shake subsided and is all but gone. Just a tad shake noticeable upon engine start, but nothing to worry about. Thanks for the encouragement guys!