HELP - Today for the first time my engine idled very unevenly as if it was only using half the cylinders. It happened 3 times on a 40 mile round trip. Each time while sat stationary in a queue of traffic in gear. Putting it out of auto and into neutral made no difference. Each time when I depressed the accelerator the uneven idle went away and did not return until later in the journey despite idling in traffic many times. The engine has never stalled and no obd codes were thrown. It sounds and feels like not all the cylinders are firing.
What would cause this, perhaps CPS sensor on the way out?
2006 auto with 57k miles