Damir, hi. First read:
Is the injection Bosch L/LE type or K? If L you need to raise the fuel delivery pressure to enrich the mixture, you should not attempt alterations to the flowmeter/mixture screw. This may solve the problem - if you are lucky. Set the ignition timing to std setting, blank off the vacuum advance
and use the 7 grade plugs.
You need to get a 0-50 psi fuel pressure gauge in the inlet manifold fuel rail, make a note of the fuel delivery pressure at idle. Fit an adjustable fuel pressure regulator and increase the idle delivery pressure by 5 psi
. Set the enrichment screw to give factory CO emission at idle - without cat I imagine 2.5-3.5% CO. You need a proper gas analyser to do that. Then road test with that and see if it improves the engine. You can raise it higher if need be but in my exp 7psi is about the limit. i have done this, it may work.
Report back when you have done this. I would like to see a photo of the air flow meter system, to be honest I don't know what is fitted on that unit.