A p0340 on this vehicle doesn't necessarily mean a circuit failure (wiring, sensor or pcm). The strategy that sets this code looks for a signal at the appropriate time, and if it is not seen within about 25 degrees of crank rotation, the pcm will log this code. If it happens on two consecutive drive cycles, the check engine light will turn on. A timing belt or pulley issue will cause this same code, however, your symptoms aren't quite what you'd see with a timing belt problem. Based on that, wiring is the first place i'd go. Second, scoping the appropriate lines at the pcm while the engine is running will tell you if the signals from the cam and crank sensors will let you know if they are the cause of the problem. RFI is a very real problem on todays cars - but it is usually generated from the old aluminum DPFE sensors (which your's doesn't have) or coil-on-plug ignition coils. On your car, the alternator, coil pack and cooling fans all can generate rfi that would interfere with low voltage signals like the cam sensor signal. Find you a good shop with knowledgable people to work our problem.
