2003 Nissan X-Trail Sensor issues

recently my car became very hard to drive. Stalling at roundabouts, loss of power when pulling away and sudden loss of power when driving normally. I know sounds like crankshaft sensor, I was told it could be a cam sensor, I got both. Replacing the crankshaft sensor first made no difference. Replace the cam sensor and it did get better, but still have the issue every now and then. By the way I have tried three old readers and they don't work on this vehicle, maybe there is a custom one? Our attention turned to the maf but it looked clean. We unplugged it and again it was better for a while but then it was back. We disconnected the battery for a hour and reconnected the maf. And now the problem still exists but at least it is drive able but very annoying. Can you shed any light?

Neil