I would expect you would here chain slap in the timing cover if the chain or tensioners on one or both sides were failing. Otherwise physical inspection by removal of the timing chain cover would be the next best route. It may be beneficial to take the car to a reputable tech with the diagnostic interface which I would assume could run tests on the VCT solenoids and see if inconsistency's exist that would isolate the problem to a solenoid issue. It does make sense being you are getting the two intermittent CEL's. Commanded timing position of the VCt and actual not matching could trick the PCM into thinking it is sensor related to the crank or cam sensor.
One last thing. You aren't running an oil thicker than 5w30 are you, or recently changed to a thicker viscosity before this started to occur? The VCT timing system has been known to be sensitive to not work well with thicker viscosity oils. I was asked this when my phasers failed. Made sense. I assume you are not however. But IF you are try changingthe oil back to a 5w20 synthetic of synthetic blend and see if the problem goes away since it is intermittent from your description. Sounds kooky I know, but does make sense, and if you have been for some time age may be the culprit as to why it has not had any effect until now. Good luck.
