[3.1L Z]

In reference to my wife's 07 X3 but thought you guys could help. Ran the codes getting misfires on 3 cylinders. This only occurs at idle, car (AT) jerks forward like someone slightly hits the car from behind. Once the car is going is smooth as silk. At idle with the AC on its worse. I've switched the coils around, still occurs but no new codes yet so I can't say its coils yet. Anyone know what would cause the misfires at idle? Its very noticeable. The plugs only have 10K on them.

thanks
Steve

[jeddo45]

Have you ever changed the coils? If you haven't had them changed, then several of them might be going bad which means switching them around isn't going to do you much good. I would just change them out.

[3.1L Z]

Its got 90k. Original coils and injectors. Would either one of these exhibit problems at idle but do fine at regular driving?

[jeddo45]

Originally Posted by 3.1L Z

Its got 90k. Original coils and injectors. Would either one of these exhibit problems at idle but do fine at regular driving?

Ita going to be your coils. I'm surprised you got 90k out of them and you're barely having issues. Your fuel injectors would have consistent issues so I don't think that's what's bad, although I'm not entirely ruling that out. If your engine has ever went into limp mode then maybe.

What it sounds like is your coils. When I had my 328i, the only thing that was bad was the idle. It drove fine. Once I changed the coil, the rough idle went away.

It would be good if you change all of them at the same time. Not only are you future proofing, you should notice a performance bump.

[3.1L Z]

Holy shit. I really need to write stuff down.
Don't think I did the plugs last year. Could worn out coils do this?
I usually put anti seize on plugs and nothing on these. Pretty tight as well so it makes me think I never did the plugs. On second thought these might be the Irdium plugs that have the tiny electrode...

[3.1L Z]

Here's another shot.

[jeddo45]

I think its very safe to say we found the problem . Your car just needs a tune up that's all!

If I could recommend some parts, here is what I bought for mine:

Coil Packs: https://www.amazon.com/Bosch-0221504...sch+coil+packs

Spark Plugs: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

I'm pretty confident this should fix your idling problem. Easy DIY too!

[LeMansBleuXI]

yup sounds like new plugs and coils are due! Just did mine last weekend at 56k and cars running like new again. $229 for 6 bosch plugs and coils, simple job if you take your time and go step by step. Used this DIY and it was seamless

good luck!

[3.1L Z]

Well, new plugs and no more misfires. I must not have replaced the plugs. They could have had 90k on them.... Bought the car with about 40K on the OD. I'll get some new coils for the hell of it since they're cheap and probably needed soon anyway. Thanks.
steve