Audi Q5 Diesel Performance Drop Points to Injector Fault

Last month I dealt with nearly identical symptoms on my 2016 Audi A6 TDI. The initial symptoms match perfectly, power loss, jerky acceleration, and increased fuel consumption. The root cause turned out to be a faulty fuel injector that was causing uneven fuel distribution. Modern diesel fuel injectors are highly precise components, and when they malfunction, they significantly impact the air-fuel ratio. The diagnostic scan revealed trouble codes pointing to cylinder 3 injector. The repair required: Complete fuel injector removal and testing, Replacement of one defective injector, Recalibration of the injection system, Cleaning of the intake manifold as a preventive measure This was indeed a serious issue requiring immediate attention, as continued driving could have led to: Engine damage from improper combustion, Increased emissions, Risk of additional injectors failing, Potential damage to oxygen sensors The repair took a full day at the shop. The symptoms completely resolved after replacement, and fuel economy returned to normal. Given your mileage and symptoms, I strongly recommend having the fuel injectors tested with proper diagnostic equipment.

Thanks for sharing your experience. This definitely helped confirm my suspicions about the fuel injectors. I will get them checked right away. How much did you end up paying for the entire repair? Also curious if youve had any recurring issues since the fix? My check engine light seems to act up more frequently these days so I want to make sure I address all potential problems at once.

Since having the faulty injector replaced, my engine has been running perfectly with no check engine light issues. The repair cost came to 515 Euro total, which included diagnostic testing, parts, and labor. The mechanic confirmed the engine was running too rich before the fix, but the new injector completely resolved this problem. The fuel economy is back to normal levels, and the engine runs smoothly during acceleration without any jerking. I recommend getting a proper diagnostic scan to confirm your injector issue before proceeding with repairs. Some shops will try to upsell additional services, but in my case, replacing the single defective injector was sufficient. It has been 6 months since the repair, and I havent experienced any related problems. The initial symptoms you described, power loss and rough running, were identical to mine, and fixing the injector resolved everything. When the intake manifold was inspected during the repair, it showed no additional issues that needed attention.

I followed through with getting my car checked based on these suggestions. Took it to a different mechanic who specializes in diesel engines. The diagnostic scan confirmed a failing fuel injector, exactly as suspected. The repair cost was 485 Euro for the injector replacement plus an additional 95 Euro for cleaning the intake manifold. They also checked the oxygen sensor and spark plugs while the engine was opened up, but those components were fine. After a week of driving, the difference is remarkable. The engine runs smoothly with no power loss or jerking during acceleration. Fuel consumption has dropped back to normal levels and the check engine light has stayed off. The mechanic found carbon buildup in the intake manifold, which they said was contributing to the rich fuel mixture. The thorough cleaning seems to have helped restore proper airflow. Really glad I addressed this promptly before it could cause more serious engine damage. A bit frustrated my previous mechanic missed this, but relieved to have found someone who properly diagnosed and fixed the issue. The car feels like new again.