rs90m3

Hi,
glad to have found this site along with 20v.org...anyways,i have a 91 cq (140k)and i'm experiencing a misfire which i think is on the #3 cylinder.i replaced the wires,cap,rotor and spark plugs w/c really did not help-i even swapped in some injectors i got from a parts car w/c are known to be in good working order.now i'm kinda stumped here-is there maybe another possible cause to this-i heard that the distributor gears are plastic and poss.sheared a tooth,would this produce a misfire?
i bought the car 3 months ago as a project car-the engine started doing this about a week ago.any suggestions on where to look? thanks for your help....
BTW:how rare are the 20v 5 cylinder engines-there's a coupe quattro at my local salvage yard that still has the engine and transmission-i was thinking of pulling the cylinderhead for a future spare.....

CvTech

sad...CQ at salvage yard