I've had a P0340 (cam sensor circuit) coming up intermittently for a couple of weeks. It's had two new cam sensors fitted, but still the fault occasionally pops up. The MIL light went off after a while though, but the fault is obviously still there as sometimes the ECU is restricting the revs to 4000rpm. Usually when it's going to do this it takes longer to start (though the starter is still turning the engine quickly).
Now, I've heard in several places that a faulty crank sensor can also cause these symptoms, and I know that P0340 can be nightmare to pin down what's actually causing it (had the timing and belt tension checked too).
But wouldn't it maybe log a crank sensor fault at some point if this were the case?