CM214 can refer to either crankshaft or camshaft position sensor, depending on wbhich your engine has. It can also refer to a problem in the ignition module, or bad wiring between any the CKP/CMP and the ICM and the PCM. Much of the time, a CM214 is associated with a no start, in that the computer doesn't ever get the CID signal, and so it doesn't fire the spark plugs. The fact that the engine runs suggests to me that the fault in the CID circuit is intermittent. Meaning that the computer is getting the signal enough of the time for the engine to run, but losing the signal occasionally, causing the code to be set. If it is intermittent like that, it could be pretty tricky to track down.