The mid range misfire seems to off gone away. Not exactly sure what fixed it, but according to the VAG ECU start-up procedure i missed a few steps out.
The first is to let the coolant temperature to reach 80C, I didnt do this before as I had my adjustable fan thermostat set to 50C, as I was running in the garage.
Also before sarting up the engine, the ignition needs to be on, as the ECU will go through some tests to calibrate the throttle control.
Also found a fault on the MAF sensor, near the air filter, when "wiggled" the engine note changed, on inspection the power pin blades were open too far, maybe making and breaking contact with the sensor. Fixed that a found some exposed wire on the same sensor where it passes through the rear bulkhead.
Anyone of these could of been the fault, or maybe a mixture of the all.
I connected the swirl pot to the main fuel tank, to rule out a fuelling problem, and temporarily sealed the the fuel gauge hole with an aluminium plate and gaffer tape.
I can now rev the engine pass the mid range, and upto some high revs, without any misfire. Blipping the throttle to fully down and then releasing, the engine pick up is quick and controlled. So overall all I think the engine is now sorted.
I also set about connecting up some indicator bulbs, both side repeaters and rear indicators. All are working and the pulse period is good, the relay can be heard clicking in and out. Dash board warning lamps are also working.
Replaced the oil switch (M10 from CBS), and this now behaves, with the new switch now going open circuit when pressure is reached, the oil warning lamp goes out when the engine is running. The oil switch is located top right of the oil filter housing, the exisiting wiring connection is not compatible with the new oil switch, so this needs to be removed and a 6.3mm spade fitting.
Need to make a handbrake mount, that will be tomorrows job !! :)