The ECU does not really need the cam sensor. It's only used for sequential injection, which requires 720 deg sync. In 360 deg sync (without cam sensor signal) the ECU injects half the fuel at every revs and the engine runs reasonably fine!

That said I'd check the crank sensor: make sure the gap is within specs. This is the one sensor you really can't do without and the ECU can easily lose sync if the gap between the sensor and the trigger is too wide, which causes bangs, pops and all kinds of nasty stuff.