Q7 Injection System Failure Causes Major Performance Drop

Had similar issues on a 2005 Audi A6 3.2 FSI. The symptoms match classic fuel injection system failure. The main problem was a faulty fuel pressure sensor and damaged wiring harness connecting to the injection control module. The repair involved: Testing fuel pressure in the system, Scanning for injection timing errors, Replacing corroded wiring connectors, Installing new fuel pressure sensor, Reprogramming the injection control module This was a serious maintenance job requiring specialized diagnostic equipment. The power loss and excessive fuel consumption came from the system running rich to compensate for incorrect pressure readings. The black smoke during acceleration confirmed the fuel mixture issues. Proper repair requires an experienced technician familiar with direct injection systems. Better to have this fixed soon, as continued operation can damage catalytic converters and oxygen sensors. The stalling at idle indicates the problem is getting worse. Look for shops specializing in VAG fuel injection systems, not general repair facilities. They should be able to properly diagnose if the issue is sensors, wiring, or mechanical injection components.

Thanks for sharing your A6 experience. Those injection system problems sound exactly like what I am dealing with in my Q7. Did you have any other issues pop up after the initial repair was done? The symptoms are identical, poor engine performance, high fuel consumption and that annoying stalling. Really concerned about potential damage to other engine components if I keep driving it like this. Would be helpful to know roughly what the maintenance costs were for your repair job. Just trying to budget properly since these fuel system repairs on Audis can get expensive.

Since getting the injection system fixed at the specialist repair shop last month, my A6 has been running perfectly. The engine performance returned to normal and fuel consumption dropped back to regular levels. The stalling issue completely disappeared after they found and fixed a loose cable connection to the injection control module, total repair cost was just 95 Euro for that specific fix. The key was catching the problem early before it could damage other engine components. The petrol injection system issues can cascade into bigger problems if left unchecked, but regular diagnostics helped identify the exact fault. A properly working injection system means optimal fuel delivery and engine performance. Would definitely recommend getting it checked soon while the symptoms are similar to what mine were. Quick intervention prevented any additional engine damage in my case, which could have led to much costlier repairs.

Finally took my Q7 to a specialized workshop after seeing your feedback. The mechanic found multiple issues with the fuel injection system, exactly as you described. The main culprit was a failing pressure regulator and damaged wiring, causing the engine to run rich. Total repair costs came to 780 Euro including parts and labor. Not cheap, but the maintenance was worth every cent. The engine runs smooth now, no more stalling at idle, and fuel consumption is back to normal. The black smoke is completely gone too. The system diagnostic showed no permanent engine damage, which was a huge relief. The mechanic explained that fixing it early prevented issues with the catalytic converter and other components. Really glad I did not wait any longer to get it sorted. Best decision was switching to a specialist shop that actually knew petrol injection systems. They completed everything in one day, unlike my previous mechanic who kept the car for a week without solving anything.