[Ambro]

Purchased this `06 Carrera (997) Cabriolet with manual trans, about a year and a half ago. Early on, I started to experience intermittent misfires independent of speed, gear, or on freeway or surface street. Took it in to the Porsche Dealer who sold it to me, and they determined faulty ignition coils and spark plugs to be the source of the misfires. They also performed a Porsche multi-point inspection with satisfactory results. A few weeks later, the misfires started up again, and again I took it back to the dealer. A week later, I was notified by the dealer that they could not duplicate the symptom and could not identify the fault code to home in on the problem. I've driving the car for the past several months tolerating the same intermittent misfires. I really can use some help/advice.
Thank you