Hi All,

Thought I would update this as it completes the thread. There is another thread I opened "2013 V8V - Engine Bay Fuse F26", that turned out to be the same thing. Basically it was the secondary air pump that had failed and was causing my issues.

Here is the post (to save people looking for it):

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Hi All,

I thought I would update this (it's been a while), and I hope it helps someone in the future.

Long story short, I replaced the secondary air pump, and it immediately resolved my issues. I had read somewhere that removing the inlet manifold/plenum was quite involved, and I would agree with that assessment. A few things to take note of from my experience:

• The bolts (M8) at the rear of the manifold are really tricky to access. You will need a good socket, a small extension bar, and some patience.
• Someone (before me) had done me the "favour" of cranking down the 10 x M8 bolts with excessive force. I sheared one removing it, which I managed to slowly and carefully drill out, soon followed by two others which I just about got out in 1 piece. I replaced all of the bolts with new ones direct from my AM dealership, as they are only £0.31 each.
• The new bolts should be torqued to 25NM - which mine are. There are reports online of them being 21nm, which I am sure is fine. When at the AM dealership I had a chat with a tech, who confirmed they should be 25nm. Please do not overtighten them! The generic torque settings in the workshop manual also states 25nm.
• There are 3 x (8mm, I think) bolts on the rear of the manifold that support various cables/brackets. These are a nightmare to remove and reassemble due to very limited space and no way to see what you’re doing.
• I found my endoscope really handy when accessing the rear nuts—not essential for the job, but very helpful if you have one.
• The pump itself was really easy to replace once you have access. There are 3 or 4 bolts, some plugs, and hoses to remove. There are 2 hardline pipes at the rear that need to be detached and reattached—these are pretty obvious and I used a small adjustable spanner.
• The manifold gaskets (I used new ones) can be a bit tricky to get into place when sliding the manifold back on. Just take your time with these—they will fit. The workshop manual mentioned using glue, but I wasn't keen on that approach and felt it wasn’t necessary.
• The workshop manual also states you need 2 people to lift the manifold out. I managed to do it by myself, but having 2 people would have made it a bit easier.
• Be prepared to explain to your significant other why you have a ton of bruises up and down your legs. Leaning over the car for a couple of days will definitely leave its mark and reminded me of my rugby days.

All in all, it took me 14 hours from start to finish to replace the pump. I lost a lot of time dealing with sheared bolts and figuring out the best way to remove the manifold. Next time, I could do it in half the time.

Most importantly (for me), this has resolved all my issues. No warning lights, the car runs perfectly, and it's leaps and bounds better than it had been. Honestly feels like a different car - 100% worth the effort (and the bruises).

Hope that helps!
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