Even if the CAS is in the correct idle position, because of the teeth on the gears of the crank angle sensor which interfaces with your camshaft is prone to wear, your timing will change through higher rpms. So what i did on my ca18de was advance the timing so it would run right when it was about 3500rpm and the having it retarded on idle - probably not the best setup i know - but it was okay for what i was running.
At the moment my casualty count for timing and ignition is 12 coils packs (six on the 34, six on the exa thru 7 years of ownership), 2 power transistors and 1 crank angle sensor and a partridge in a pantry. This problem has plagued nissan motors for the last 15 years. If i had known about bosch and splitfire replacement coils earlier, i would've saved heaps of man hours wasted on diagnosis.