I've had some problems with cam sensor on 4 pot myself.
The easy way (for me) to check if it is the cam sensor, is to remove the spark plug and touch any screw on the top of the engine head, so that you close the electric loop. Second person have to crank the engine (since there will be fuel in piston, please be careful), if there is a spark on the plug it means that the problem is with fuel (ex. fuel pump, fuse etc.) or timing (little possibility).
NOTE: do not touch the engine during test nor the spark plug. Hold the HV cable not the plug.
If there is no spark on plugs (check all 4 of them) than the most possible is the Crankshaft sensor. Of course it might be as well faulty DIS pack or wiring, but as I said on 4 pots the sensor is most possible.
If there will be spark on some plugs, the most possible is DIS pack or wiring from ECU to DIS or HV cables.
Furthermore, I know it is quite hard to change the Crankshaft sensor due to the AC compressor and I know that some change the sensor (I did it
) without removing the AC compressor, it is doable but the problem is the screw holding the sensor to the block, if some one did not tighten it, it might screw itself out and change the readings of the sensor.
Check it