Thanks Jim, I purchased a smoke tester last week and of course the cone was too small for the maf inlet which resulted in an unsatisfactory bodge with a ploy bag and gaffa tape - but did get me as far as leaky throttle body seals - which are hopefully fixed. Looking for a better smoke cone adapter to continue the inlet testing.

I actually purchased a pair of coil packs so I could do some swapping with known good parts - but yielded nothing.

compression is good and consistent across all 8 cylinders

I will look at the wiring - that’s a helpful steer.

As background the Code only gets thrown under load

I am concerened though , hence the original post, that the ECU mapping is non-standard and would really like to put a standard map on as I can’t be sure what could have been mapped out.

A standard MAP would be good IMO, especially with the recent move to leaner running E10 fuel (presuming it was remapped with the good stuff)
Misfire under load sounds like a weak coilpack but you've eliminated that, weird. Maybe it is the wiring/connectors, they're old AMP/TE Junior-Timer connectors that have crimps that have a tendency to get a bit loose over time
 
A standard MAP would be good IMO, especially with the recent move to leaner running E10 fuel (presuming it was remapped with the good stuff)
Misfire under load sounds like a weak coilpack but you've eliminated that, weird. Maybe it is the wiring/connectors, they're old AMP/TE Junior-Timer connectors that have crimps that have a tendency to get a bit loose over time
Yes, weak coil was exactly what I suspected - hence I rushed and bought some - I went down an initial blind alley with the wrong cylinder as I didn't look properly at the two cylinder numbering options!

I also possibly need to run it longer to see if I get any other codes. The problem is, as soon as the misfire on 5 triggers it's in limp mode which doesn't motivate me to drive far!
The injector on 5 is definitely doing something - whether it is working properly is another matter - but no codes are being thrown for injectors.
 
I'm guessing the map isn't standard, as you've not mention low cat performance, which is something the factory map will definitely show, it'll put the MIL on too, if the cats aren't working correctly.
 
I'm guessing the map isn't standard, as you've not mention low cat performance, which is something the factory map will definitely show, it'll put the MIL on too, if the cats aren't working correctly.
Sadly as the cats have been gutted and are no longer present it suggests that the downstream sensors are mapped out
 
Ok drove to Swindon yesterday, took it easy all the way to avoid triggering to early and having the pain of limp mode.
But I earned myself some new codes…

Misfire on 5
Misfire on 7
Low cat efficiency bank 2
Too lean bank 1

5 and 7 are on the same side - bank 2

The car starts on the button, it does smell extremely rich

I think I will pursue : a more comprehensive smoke leak test
Maybe delve into the injectors and see what the spray patterns look like.

I don’t have the equipment to do a proper sonic clean, but I do have a useful pressure device which should allow me to look at spray patterns - it’s only an eye-ball check but it may do for starters

I haven’t ruled out fuel pressure/pump/filter

…and I’d still like to get a ‘proper’ map file
 

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