[4AGE] ignition timing problem -> SOLVED !!

[Bean]

Sounds very tricky... so the only thing jumping in to my mind right now are three things.
1. are you sure your diagnostic plug still works? as mine doesn't i.e. if I jumper the terminals the timing doesnt change - means I have to set my timing at idle to 16° instead of 10° (workaround would be to jumper the terminals directly at the ECU)
2. have you done a compressiontest to see if your cylinders have equal and sufficient sealing
3. can't realy tell how to check this in a safely manner but maybe your cold start injector (the one in the plenum) is stuck - this would result in too much fuel and worse an metered fuel being injected... can you make a good picture of your plugs as this will help diagnose the problem...

PS: nice clean engine bay reminds me to clean mine as it more than just dusty right now, but that's no surprise in this country.