Hi, my name is Devin. I am an auto repair expert with the Car Genius team here at RepairPal. I'm sorry to hear you're having trouble with your vehicle.
If your A8's check engine and EPC lights are still coming on after replacing the spark plugs and cylinder three coil pack, the issue might be more complex. EPC (Electronic Power Control) issues often relate to throttle body or fuel system problems, which can cause misfires or performance issues, especially at higher speeds and when the engine is hot. It's possible that there could be a fault in the throttle body, an intake air leak, or a sensor issue, like the MAF (mass airflow) sensor, which could disrupt the air-fuel ratio, leading to misfires. A clogged fuel injector in cylinder three might also be the culprit, as it can cause intermittent misfires that worsen under load.
If you need more advice, have any other questions about your vehicle, or would like to get connected to a RepairPal Certified shop near you, we have you covered. Give us a call at 877-913-1554, and we will happily help you out!
