Check to make sure the ignition coil is switching on both sides. The coil is actually two coils in one unit. One fires cylinders 1 & 4, and the other fires cylinders 2 & 3. On the coil unit is a plug with three wires. The centre wire is a common live ignition supply to each of the two coils, and the two outside wires are the ECU switch for each coil. If you have a noid lamp connect it to the plug to the centre terminal and one of the outer terminals. Crank the engine and the lamp should flash. If it does then one of the coils is being switched. The connect the lamp to the centre terminal and the other outer terminal and crank the engine again. As before the lamp should flash. If it does not flash then the coil is not being switched. This is likely due to a failed ignition module which is an integral part of the ECU, or a poor connection or broken wire between the coil unit and the ECU.