Mr.F
Inactive
Please don't try this at home unless you are very sure of the principles involved! The only way to be sure you are not introducing a damaging level of advance is to set the timing with a timing light.loosen off the distributor and give it a turn on the markings . Trial and error, and run it for a 1/2 mile and see. If no better try a little further adj, and test again. Your not doing any harm apparently, so fiddle about with the setting until it runs nicely.
Further on the misfire problem - from your ECU fault codes, the most likely culprit is the air flow meter. See if you can swap a "known to be good" unit from another car...
Second favourite would be the crank angle sensor in the distributor - need to be able to swap the whole unit.