I have put a timing gun on the car last night, the ignition advance seemed to work OK in neutral, as revs would rise, the igntition timing would advance, so at least there is no vacuum leak to the distributor advance.
I may get a fuel pressure test done on Saturday, just to rule fuel delivery out. The fuel filter is somewhat stubborn, the nuts on the bracket have rusted and are coated in liquid wrench waiting for me to get home.
I will also check the resistance on the ignition wires and spark plug caps when I get home tonight.
Anyone ever have any problems with their warm up compensator? I would have thought that it would provide a consistent problem, not just one that would show up under load. Another potential souce of problems could be the pressure step switch located in front of the windshield wiper reservior beside the horn, which was added to 1985 cars. It richens the mixture under acceleration on 1985 US spec cars. Anyone ever seen one of them fail?
I also note that the problem only surfaces when the car is warm, after it has idled for a while.
I took myself to "school" last night on all 44 pages of the CIS-E fuel injection system as set out on the CD Rom. Complex, isn't it?