Eric if that's locked at the service position via a dummy crank sensor locking tool, it most certainly will effect performance, if advanced then the spark ignites a very low compression gas mix. I'm certain you found your answer (I think I may have suggested timing earlier in the threat...just saying Guides are indeed shot so sump pan inspection and possibly a new pick up pipe.

 

That was also my very first reaction, but the mechanic says he is sure it is in the correct locking position.
I will pass by this morning, but I trust him on this one.

Sean, engine was locked as per Jaguar instructions for a AJ26 engine, using the correct tool from the timing set most people use on here.

And yes, you mentioned the timing before, it was on my list, thanks for that!
That time we checked spark advance (was correct), now, with the engine open, it start to seem obvious they did a pretty bad job in Japan.
I just ordered a new partial breather hose (snapped in the process), and also a sump seal, we will clear out the sump.

Finally, did you see how they bolted the secondary tensioner down?
They obvious didn't have the shorter bolts ....



EDIT:
Just back from a quick look at the car.
Crank was correctly locked, no mistake there.
Passenger side (LHD) was off, but very limited
Driver side (LHD) was ~1 tooth off for both intake and exhaust.

I guess they either timed the car without the proper tools, or they forgot to take slack out of the chains at some point.
Surely they did not check their own work.

Going back to the initial symptoms, it should explain the irregular idle (although not too bad), the backfire in the exhaust if you blipped the throttle at idle, and the cam-code which kept coming back.

 

Camshaft sprocket slipped somehow ?

 

The way they're assembled you'd think that's possible but I've never seen it happen, and on both would be very unusual. No, it's a crap timing chain tensioner job, as seen by Eric's shot of the tensioner bolt 'shims' - once back were they should be there will be a transformation in performance.
1 Tooth = backfire after blip, bad idle and cam code and feels like the supercharger isn't plugged in! (solid info)
2 teeth = multiple misfire codes
3 teeth = new engine

 

Crappy it was for sure.
The timing cover had a big patch of red sealant on the passenger side.
After removing, lots of cracks appeared, probably from over-torquing the tensioner.
Now re-welded.

Car is coming along fine now.
Final partial breather hose arrived last night (it snapped in spite of being sooo careful), the SC has been cleaned, and fitted with fresh bearings, oil, etc.

With some luck everything will be together by tonight, really wondering how the car will be performing if finished.
Some pictures, and yup, those bolts were not forgotten ....

 

So everything went back together today, refreshed S/C, new liquids, new hoses, timed correctly .... and all plastics cleared our of the sump.

Now the good news is, the cars pulls like a jet on steroids ... so there is absolutely no doubt the work paid of, or that the owner will be happy.

In hindsight, what still surprises me till today is that the car ran so smooth.
I should have had expected a much rougher running car (surely on idle), and a big discrepancy between the left and the right bank in fuel trims etc.
Nothing of that though, the CAM sensor code was probably the only one which came close.

Rest me to say a great THANKS to all of you who helped with this one.
Without all the info and considerations supplied, I probably should have gone an other (and wrong) path, so really really thanks!

 

Awesome news Eric! It is always nice to her of a successful chain change. So many out there ignore the chains and then when too late complain.

 

Great to hear it's going like it should Eric Your description is spot on, taking off in a jet is that lovely R engine's specialty!
I know parts aren't easy to get Taiwan that oil pickup I always change so I don't have to pick out all the little bits - Good tech at work there, I like the Japanese spanner, never seen tools like that but I'm happy with my Teng stuff Eye out for a new timing cover at some point down the road, or leave the weld as good?

 

That spanner is a standard tool here

 

It is even down here in lil ole NZ

 

I should have said 'from Japan' we all use flex spanners, but not from Japan.