carlova78

So, we have a 2007 530i with 60k miles and I thought I'd change the spark plugs because the mpgs were so so. (Not 350+ like my e39).

I replaced all 6 last night with NGKs, same part # as originals. After putting everything back together, I start the engine and it had a small misfire. I drove it around the neighborhood and the ses light came on.

Afterwards, I scan the car, and it says misfire cylinder 2. Funny thing is, cyl. 2 has a new coilpack I replaced a few months back. I swapped coil packs 1 and 2 and there's still a misfire.

I will try putting the old spark plug back in. Maybe the new spark plug is bad?

When the code reader says cylinder 2, does it confirm that it is coming from cylinder 2?

Thanks.

E60I

Do the following:

1. "Carefully examine" the wire harness (it has three thin wires) that is connected to the ignition coil. You might have broke the insulator when you pulled it apart from the ignition coil.

2. Make sure the spark plug is properly torqued and the ignition coil is properly connected to the spark plug.

Good luck!!!

BMW535xia

So, will a "misfire" code for any cylinder trigger an SES? Or, just connect the code reader to determine? Car has rough cold start after setting overnight, and thought it may be coil, injector, spark plug related.

Pitch Black

Only because this happened to me.

Are the spark plugs torqued to spec? Are the new plugs gapped to spec?

If so, bad plug. Swap plugs with another cylinder and see if the misfire moves.

carlova78

They are pre-gapped.

And no, I don't see a need to torque spark plugs. I always to it by feel and never had problems.

I'll try that! Thanks

carlova78

Yes it will, but sometimes there will be a "pending" code and it'll trigger it in the future.

Pitch Black

I didn't too. I hand tightened my N54 plugs and I had codes on all cylinders. I got my torque wrench out, cleared the codes and all of a sudden no problem.

BMW535xia

oh yes...pending codes. waiting to hear from my indy about the cold start issue after having brake fluid flush/fill, oil/filter change, service resets done today. thanks...

carlova78

UPDATE:

Okay so I played around with it tonight, swapped the cyl. 2 spark plug out with the old one. Misfire was gone and it ran smoothly. I put the new one back in, and all was well. I must have left something loosely connected after all. Hope the MPGs go up now!

Thanks for all the input guys!

Pics of the car btw.

tonyb635

I hear proper torque on these plugs is most important. The only possibilities I see with what happen is like you said something may have not been connected correctly OR you achieved a better torque this time...