You have emission tests on a vintage vehicle
Oh boy! Not even here in totaly over regulated Germany they send pre 1978 cars to that test.
Here is a trick we used with good results: Drive the tank almost empty and than buy a view gallons of the highest octan fuel in you can find.
Than enrich this with octan booster.
Now you can advance the ignition much more than usual.
Now create a temporal vacuum leak.
I don`t talk about pulling the wiper hose, but just let a bit air in the intake by loosing a clamp or something like this.
So you can lean it out better as with the air screw without hurting driveability to much.
It works like those air bleed gadgeds.
That should do the trick.
If you passed the test, go back to what you had.
good luck, Frank
