06 X5 3.0 Code PO302 PO303 PO 305 and PO300 Misfire

[crystalworks]

Originally Posted by Effduration

What are those codes? I am not looking them up...

No kidding. So frustrating when an op doesn't post the definitions with the codes. Help us help you.

Edit: I see the "misfire" in the title of the post now. Random misfires are usually vacuum leak related as cn90 points out below. Intake bellows is a good place to start but it can be in so many other places. Smoke test would be the best way to diagnose. Otherwise you'll have to start pulling parts for visual inspections. Good luck.

[cn90]

Multiple misfire codes usually point to air leak.

The #1 culprit is the rubber boot feeding the throttle body.
The cracks are usually on the underside, which you can only see once it is removed from the car.

[cn90]

Cracked rubber boot...I posted the photos here...

https://xoutpost.com/bmw-sav-forums/...ml#post1204411

[FREE100KSECRET]

Originally Posted by cn90

Multiple misfire codes usually point to air leak.

The #1 culprit is the rubber boot feeding the throttle body.
The cracks are usually on the underside, which you can only see once it is removed from the car.

Thanks, agreed, but in my case it started with just #3 misfire and open injector circuit, so I discounted rubber boot as it was not a random misfire, but consistent, so I ordered new injector, but then #2, #4 came up with same codes, PO300 and PO303, 302, 304, so now I don't think all injectors would be open circuit at the same time. So I was curious if anything else could cause problem. I checked boot, no vacuum leaks detected anywhere, so I am stuck. If all cylinders had random misfires, I would agree.

Thanks,

[FREE100KSECRET]

Originally Posted by crystalworks

No kidding. So frustrating when an op doesn't post the definitions with the codes. Help us help you.

Edit: I see the "misfire" in the title of the post now. Random misfires are usually vacuum leak related as cn90 points out below. Intake bellows is a good place to start but it can be in so many other places. Smoke test would be the best way to diagnose. Otherwise you'll have to start pulling parts for visual inspections. Good luck.

Sorry, I just assumed most know most of the codes by heart, so I was wrong, the misfire code is probably the most common of all codes, PO302 open injector code is also common, so I made the mistake of assuming most would know what they are related to, will better define problem rather than codes next time.

Thanks