I vote for the CPS sensor. I would get the occasional hard start so I replaced the CPS sensor. Then, with the new one, (Borg Warner) the car would quit driving down the road every time I reached 4000 rpm. Put the stock CPS sensor back in and no trouble of any kind for the last year. Apparently it was a loose/bad connection between the sensor and the plug on my car. I would start by disconnecting, cleaning and reconnecting the plug. And don't forget to get the error code.

Les