2003 540i/A P0011 Code

[Foxhole Norman]

Hey all, having a little issue with my Euro 540i/A with 142k Miles. About 2 months/1300 Miles ago I got the Chains/Guides/Tensioners, the whole lot bar reconditioning the VANOS as that would've been too time consuming waiting for parts (being my daily) and wasn't the biggest deal to me as I knew(thought!) that even when they're faulty all they tend to do was knock around. For about a month and a half everything was working perfect, lovely smooth idle and not having to worry about the timing system, however on the 1st April I started her up to disembark the ferry after arriving in France and I noticed a little stumble in the idle, randomly stumbling too. I passed it off as the ferry ramps moving as cars disembarked but once out driving I could feel the hesitation on harder acceleration. Driving normally and cruising you wouldn't feel a thing, only when coming to a stop and idling or accelerating hard would you notice it.

Now there's no engine light at all accompanying the error code other than it will flash if you go to say kickdown a few gears and accelerate very hard and will throw a pending code for a cylinder 8 misfire. Now my question is what would cause this constant P0011? I know for most it's the death knells of the guides but they were just done and working perfectly until all of a sudden nearly two months on this happens. Once back in Ireland I got it to my mechanic who did the Timing job for me and he said it was coming back with a VANOS actuator fault. We ordered the Beisan seal kit and these are due to go in next week. Has anyone any idea if faulty VANOS seals can cause this or does it sound like something else? I swapped CPS sensors to no difference and unplugged VANOS solenoids to check but did not swap them at the time as I did not have a full tool kit with me in France at the time.

Thanks in advance!