The cam position sensor was replaced, and when the problem continued the cam sensors were then swapped with no effect. The vvt solenoids were also swapped, the PCM was flashed, and the oil had been properly changed over the last year with no issues.
I had the same symptoms with my 2014 Jeep Wrangler Unlimited. Based on your experience I replaced the Crankshaft Position Sensor. Got 8.5 miles on the highway before it threw code C0394 again.