ok remove the distributor cap and have a look inside at the phase sensor,move the heel of one of the cams (which are 90 degrees apart) by rotating the engine to line up with the phase sensor heel and measure the gap, it should be 0.2 to 0.3 mm also check for broken wires in and the connector on the side of the dizzy for damage or bad connection.its known for the wires to fray or break at the phase sensor.
its this sensor that more or less sequences the fuel injection so it may be related to the injector problem,although i would thought it would affect them all,but see how you get on