timing chain tensioner

[FREE100KSECRET]

I have 03 X5 4.4 I have been nursing to the point of 238K and have dreaded the time the chain guides go, but here is my question. I have rough idle suddenly, a little rattle at cold start, smooths out above 2K RPM. Throughs code PO0011, along with misfires fuel shut off on all cylinders on bank one, so obviously the first thing I changed was Cam Sensor, no difference. I used endoscope and guide looks good, but I did push on chain and it is looser than it should be as I recall. So my question is, would a chain tensioner cause these codes? I have never had any issues with engine, so it is original, and having searched around, I see it should be replaced at 100K intervals, so anyone know if a weak tensioner can through these codes, or is it a VANOS issue more likely.

Thanks,