Audi A6 Diesel Loss of Power Points to Cylinder Issues

Had identical symptoms with a 2016 Audi A7 TDI. The initial power loss and fuel economy issues pointed to cylinder pressure problems, but diagnostic testing revealed failing fuel injectors causing incomplete combustion. When multiple fuel injectors start degrading, it creates symptoms that mimic more severe engine issues. The turbocharger was also affected due to irregular fuel delivery, which contributed to the power loss. The engine knocking became noticeable particularly during cold starts. This required a complete fuel injector replacement and turbocharger inspection. This is a serious issue requiring immediate attention since damaged fuel injectors can lead to additional engine damage, particularly to piston rings and cylinder walls if left unaddressed. The repair involved: Full diagnostic testing, Replacement of all fuel injectors, Turbocharger inspection and cleaning, ECU recalibration, Fuel system cleaning The low mileage on your engine suggests this could be related to fuel quality issues or extended periods of short trips rather than normal wear. Regular diesel engine maintenance helps prevent such issues. After the repair, both power delivery and fuel economy returned to normal, with no engine knocking or performance issues since.

Thanks for sharing that detailed experience. I actually faced very similar problems with my Audi A6 last year. The engine knocking during cold starts and power loss were exactly what I experienced. My mechanic found issues with both the intake manifold and fuel injectors. Would you mind sharing what the total repair cost was for your fix? Also, have you noticed any new problems since the repair was completed? Just want to gauge if this is a long-term solution or if I should prepare for potential follow-up issues with my crankshaft or other components.

Just got back from the mechanic last week for a follow-up check on my A7, and I can confirm the repair has held up perfectly. The cylinder pressure fluctuation that initially worried us was completely resolved after the fuel injector replacement. The engine runs smoother than ever, especially during those tricky cold starts. Best part, the repair ended up costing 0 Euro since it was traced back to a manufacturing defect in the original fuel injectors that affected the intake manifold performance. The dealer covered it under warranty extension. Since the fix, performance has been rock solid. The fuel economy is back to normal, and there have been zero issues with the crankshaft or any other engine components. The key was catching it early before the faulty fuel injectors could cause more extensive damage to the piston rings or other critical parts. A professional diagnostic revealed this was a known issue for this engine series, which is why it was covered. If your symptoms match, might be worth checking if your vehicle qualifies for the same warranty coverage.

Thanks for the advice. Finally got my A6 sorted out last week. After reading about your experiences, I took it to a certified shop that specializes in diesel engines. Turns out my timing belt was showing early wear signs and the fuel injectors were indeed the main culprit. The repair cost came to 2300 Euro which included: New fuel injectors, Timing belt replacement, Full system diagnostic, Fuel system cleaning The head gasket was also inspected but thankfully showed no damage. The engine now runs perfectly, no more power loss or poor fuel economy. The cold start knocking is completely gone too. Would have spent way more if I had waited longer and caused damage to the piston rings. Really glad I caught this early. Will definitely keep up with regular maintenance from now on. The mechanic suggested yearly inspections to prevent similar issues.