A5 Multiple Issues Point to EGR Valve Problems

I had very similar issues with my 2012 A4, and being somewhat experienced with automotive repair, I initially tried diagnosing it myself. The symptoms you describe match exactly what I experienced, rough idle, power loss, and increased fuel consumption, all pointing toward emissions system problems. The exhaust gas recirculation valve was indeed the culprit. After taking it to my regular workshop, they confirmed the EGR valve was completely jammed with carbon deposits, preventing proper exhaust gas recirculation. The repair cost me 355 Euro, including parts and labor. The fix significantly improved performance and fuel economy. Before spending money on repairs, they performed a specific emissions test to confirm the EGR valve malfunction. The catalytic converter was also checked to ensure it wasnt contributing to the problem. To provide more specific advice for your case, could you share: Current mileage on your A5? When was the last time you had an emissions system service? Any recent changes in driving patterns? What type of fuel you typically use? Any previous similar issues? This information would help determine if your case might need a different approach than mine did.

Last serviced at 35656 KM and having this problem since then. The mechanic cleaned the throttle body and performed basic maintenance during that service, but the EGR valve wasnt specifically checked. The check engine light appeared shortly after. After reading through the responses, I think a clogged EGR valve is the most likely cause. The symptoms match perfectly, especially the rough idle and power loss. My fuel consumption has jumped from 12 to 15 liters per 100km. I will book an emissions test at a local shop. Would be great if someone could confirm typical repair costs. So far, I have been quoted 450 Euro for EGR valve replacement including labor.

Thanks for the additional details about your A5. Based on my experience with the same issue on my A4, that 450 Euro quote sounds reasonable for an EGR valve replacement. In fact, its quite close to what I paid (355 Euro), considering prices have likely increased since then. The jump in fuel consumption from 12 to 15L/100km matches almost exactly what I experienced before fixing the EGR valve. The rough idle and vehicle emissions problems started immediately after a routine service in my case too, suggesting the timing might not be coincidental. Getting an emissions test first is definitely the right move. When my check engine light came on, the test clearly showed the EGR system wasnt functioning properly due to carbon buildup. The recirculation problems were causing that characteristic power loss and jerking during acceleration that youre experiencing. One tip from my repair experience: make sure they clean the EGR passages thoroughly while replacing the valve. In my case, they found significant carbon deposits in the surrounding pipes that needed cleaning to prevent the problem from recurring quickly. The repair completely resolved all symptoms, the rough idle, smoke, and hissing noise disappeared immediately. Fuel consumption returned to normal within the first tank after repair.

The estimated 450 Euro quote seems reasonable when compared to other responses. My situation with high fuel consumption and rough idle appears to be a common issue with these engines when the EGR valve gets clogged. Taking the advice shared, I will proceed with the emissions test first to confirm the diagnosis. The comprehensive cleaning of EGR passages mentioned makes perfect sense, no point replacing just the valve if the surrounding system remains clogged with carbon deposits. I made an appointment for next week at a local shop for the initial emissions test and vacuum leak check. Really hoping this resolves all the symptoms, especially the check engine light and jerky acceleration. The current fuel consumption of 15L/100km is just not sustainable. Will update once I get the test results and complete the repair. The detailed responses have given me confidence that this is likely the correct diagnosis and repair path. A 450 Euro investment seems worth it to restore proper engine performance and fuel economy.