323 1.6i missfire problem

Hi

i have a 1993 323 1,6i 16v, wich is starting to give me a headache.

I have changed the sparkplugs,ignitor and cap, the wires, air and fuelfilter, still it slightly missfires and its most noticable when the car idles. i pulled the new sparkplugs back out for a look, and they were already black. When the car idles and i pick off the plugwires one by one, its really not a big diffrence on the idling wich one i pull off, it still missfires about the same.

i also checked the timingbelt and the ignition, and its all timed correctly.

Does anyone have any suggestion to what causes this missfiring?

Thanks in advance for ur help

Might need to check the timing...?

In my Haynes manual, there's a description of how to adjust the distributor using an inductive timing light.  Might be worth a look.