06 X5 3.0 Code PO302 PO303 PO 305 and PO300 Misfire

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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,