Audi Q8 Diesel Power Loss Points to Fuel System Fault

Had similar issues with my 2017 Audi Q7 TDI. Initial symptoms matched yours, rough running, increased fuel consumption, and power loss. The root cause was a damaged fuel injector, but the real problem started when an inexperienced mechanic failed to properly diagnose and tried fixing just the sensor readings. The ignored injector issue eventually led to carbon buildup in the intake manifold and caused engine knocking. This created uneven cylinder pressure, which then affected the crankshaft position sensor readings. The entire situation became more complex because the initial repair wasnt handled correctly. The proper fix required: Complete fuel injector replacement, Intake manifold cleaning, Timing belt inspection and adjustment, New spark plugs, Full diagnostic system reset This was a serious repair job that took several days to complete. The engine knocking could have caused severe internal damage if left unchecked. For your Q8, strongly recommend finding a certified Audi specialist who can properly diagnose the initial problem to avoid these cascade effects. These symptoms almost always indicate fuel delivery issues in TDI engines. Getting it fixed correctly the first time will prevent more expensive repairs later.

Had similar issues with my 2017 Audi Q7 TDI. Initial symptoms matched yours, rough running, increased fuel consumption, and power loss. The root cause was a damaged fuel injector, but the real problem started when an inexperienced mechanic failed to properly diagnose and tried fixing just the sensor readings. The ignored injector issue eventually led to carbon buildup in the intake manifold and caused engine knocking. This created uneven cylinder pressure, which then affected the crankshaft position sensor readings. The entire situation became more complex because the initial repair wasnt handled correctly. The proper fix required: Complete fuel injector replacement, Intake manifold cleaning, Timing belt inspection and adjustment, New spark plugs, Full diagnostic system reset This was a serious repair job that took several days to complete. The engine knocking could have caused severe internal damage if left unchecked. For your Q8, strongly recommend finding a certified Audi specialist who can properly diagnose the initial problem to avoid these cascade effects. These symptoms almost always indicate fuel delivery issues in TDI engines. Getting it fixed correctly the first time will prevent more expensive repairs later.

Had similar issues with my 2017 Audi Q7 TDI. Initial symptoms matched yours, rough running, increased fuel consumption, and power loss. The root cause was a damaged fuel injector, but the real problem started when an inexperienced mechanic failed to properly diagnose and tried fixing just the sensor readings. The ignored injector issue eventually led to carbon buildup in the intake manifold and caused engine knocking. This created uneven cylinder pressure, which then affected the crankshaft position sensor readings. The entire situation became more complex because the initial repair wasnt handled correctly. The proper fix required: Complete fuel injector replacement, Intake manifold cleaning, Timing belt inspection and adjustment, New spark plugs, Full diagnostic system reset This was a serious repair job that took several days to complete. The engine knocking could have caused severe internal damage if left unchecked. For your Q8, strongly recommend finding a certified Audi specialist who can properly diagnose the initial problem to avoid these cascade effects. These symptoms almost always indicate fuel delivery issues in TDI engines. Getting it fixed correctly the first time will prevent more expensive repairs later.

Thanks for sharing your experience. My Q8 ended up having similar problems, and I am glad I got it fixed properly. The mechanic found worn piston rings which caused low compression in two cylinders. They also discovered a hairline crack in the head gasket while doing the repair. Were there any long-term issues after your repair was completed? Would be helpful to know how the repair has held up and what the total cost was for your fixes.

Thanks for sharing your experience. My Q8 ended up having similar problems, and I am glad I got it fixed properly. The mechanic found worn piston rings which caused low compression in two cylinders. They also discovered a hairline crack in the head gasket while doing the repair. Were there any long-term issues after your repair was completed? Would be helpful to know how the repair has held up and what the total cost was for your fixes.

Thanks for sharing your experience. My Q8 ended up having similar problems, and I am glad I got it fixed properly. The mechanic found worn piston rings which caused low compression in two cylinders. They also discovered a hairline crack in the head gasket while doing the repair. Were there any long-term issues after your repair was completed? Would be helpful to know how the repair has held up and what the total cost was for your fixes.

Just wanted to follow up on your question about long-term issues. After getting everything properly fixed by a certified specialist, my Q7 has been running perfectly with no recurring problems. The initial fuel injector and intake manifold issues were completely resolved, and the engine knocking disappeared after the cylinder pressure fluctuations were corrected. The repair facility dealt with the root cause rather than just treating symptoms, and because the problems stemmed from poor previous work, they didnt charge for fixing the consequential damage, saving me the additional repair costs. The car now performs like new with stable compression across all cylinders. No head gasket issues developed, and the timing belt inspection showed everything was within specs. Most importantly, fuel consumption returned to normal levels. Its critical to address these issues promptly. A compromised head gasket or ongoing cylinder pressure problems can lead to much more severe engine damage if left unchecked. Regular maintenance since the repair has kept everything running smoothly. My advice is to keep monitoring your engine performance closely for the next few thousand kilometers, even though the repairs are complete. Any unusual sounds or performance changes should be checked immediately to protect your investment.

Just wanted to follow up on your question about long-term issues. After getting everything properly fixed by a certified specialist, my Q7 has been running perfectly with no recurring problems. The initial fuel injector and intake manifold issues were completely resolved, and the engine knocking disappeared after the cylinder pressure fluctuations were corrected. The repair facility dealt with the root cause rather than just treating symptoms, and because the problems stemmed from poor previous work, they didnt charge for fixing the consequential damage, saving me the additional repair costs. The car now performs like new with stable compression across all cylinders. No head gasket issues developed, and the timing belt inspection showed everything was within specs. Most importantly, fuel consumption returned to normal levels. Its critical to address these issues promptly. A compromised head gasket or ongoing cylinder pressure problems can lead to much more severe engine damage if left unchecked. Regular maintenance since the repair has kept everything running smoothly. My advice is to keep monitoring your engine performance closely for the next few thousand kilometers, even though the repairs are complete. Any unusual sounds or performance changes should be checked immediately to protect your investment.

Just wanted to follow up on your question about long-term issues. After getting everything properly fixed by a certified specialist, my Q7 has been running perfectly with no recurring problems. The initial fuel injector and intake manifold issues were completely resolved, and the engine knocking disappeared after the cylinder pressure fluctuations were corrected. The repair facility dealt with the root cause rather than just treating symptoms, and because the problems stemmed from poor previous work, they didnt charge for fixing the consequential damage, saving me the additional repair costs. The car now performs like new with stable compression across all cylinders. No head gasket issues developed, and the timing belt inspection showed everything was within specs. Most importantly, fuel consumption returned to normal levels. Its critical to address these issues promptly. A compromised head gasket or ongoing cylinder pressure problems can lead to much more severe engine damage if left unchecked. Regular maintenance since the repair has kept everything running smoothly. My advice is to keep monitoring your engine performance closely for the next few thousand kilometers, even though the repairs are complete. Any unusual sounds or performance changes should be checked immediately to protect your investment.

Thanks everyone for the advice and sharing experiences. I finally got my Q8 fixed last week. After checking several repair shops, I found a certified diesel specialist who properly diagnosed the issues. The turbocharger was actually showing signs of wear, which contributed to the power loss. During the repair they found metal particles in the oil, leading them to discover the worn piston rings and cracked head gasket. The fuel injector system also needed cleaning and calibration. Total repair cost came to 4800 Euro including parts and labor. While expensive, seeing the extent of damage made me realize how important it was to address everything properly. The engine now runs smooth, power is back to normal, and fuel consumption has improved significantly. The repair took 4 days to complete but the results were worth the wait. The cylinder pressure is now perfect across all chambers and the camshaft timing is spot on. No more check engine light or rough running issues. Going to stick with this mechanic from now on. Their thorough diagnostic approach likely prevented more serious engine damage down the line.

Thanks everyone for the advice and sharing experiences. I finally got my Q8 fixed last week. After checking several repair shops, I found a certified diesel specialist who properly diagnosed the issues. The turbocharger was actually showing signs of wear, which contributed to the power loss. During the repair they found metal particles in the oil, leading them to discover the worn piston rings and cracked head gasket. The fuel injector system also needed cleaning and calibration. Total repair cost came to 4800 Euro including parts and labor. While expensive, seeing the extent of damage made me realize how important it was to address everything properly. The engine now runs smooth, power is back to normal, and fuel consumption has improved significantly. The repair took 4 days to complete but the results were worth the wait. The cylinder pressure is now perfect across all chambers and the camshaft timing is spot on. No more check engine light or rough running issues. Going to stick with this mechanic from now on. Their thorough diagnostic approach likely prevented more serious engine damage down the line.

Thanks everyone for the advice and sharing experiences. I finally got my Q8 fixed last week. After checking several repair shops, I found a certified diesel specialist who properly diagnosed the issues. The turbocharger was actually showing signs of wear, which contributed to the power loss. During the repair they found metal particles in the oil, leading them to discover the worn piston rings and cracked head gasket. The fuel injector system also needed cleaning and calibration. Total repair cost came to 4800 Euro including parts and labor. While expensive, seeing the extent of damage made me realize how important it was to address everything properly. The engine now runs smooth, power is back to normal, and fuel consumption has improved significantly. The repair took 4 days to complete but the results were worth the wait. The cylinder pressure is now perfect across all chambers and the camshaft timing is spot on. No more check engine light or rough running issues. Going to stick with this mechanic from now on. Their thorough diagnostic approach likely prevented more serious engine damage down the line.