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 Q7.
Persistent misfires can indicate deeper issues, especially after replacing key components like plugs, coils, and injectors. Since misfires occur under load and at idle, possible causes include:
Carbon buildup: Direct injection engines, like the one in your Audi, are prone to carbon buildup on the intake valves. Even if the valve cleaning was thorough, residual buildup could still restrict airflow to affected cylinders.
Compression issues: Uneven or low compression in cylinders can cause misfires. Perform a compression and leak-down test to rule out mechanical issues like valve seat wear.
Fuel delivery: Even with new pumps and injectors, ensure fuel pressure and volume meet specifications under load. A weak fuel pressure regulator or clogged lines could still be an issue.
If you're still stuck, a deeper diagnostic session with advanced tools at a trusted repair shop may be necessary.
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!
