A8 TDI Manifold Issues: Misfires & Power Loss Alert

Having experienced similar symptoms with my A6 3.0 TDI (2016), the check engine light and performance issues pointed to a vacuum leak in the intake manifold. The manifold pressure sensor readings were inconsistent, which triggered the engine management system to reduce power output. The intake manifold had developed hairline cracks from heat exposure, causing unmetered air to enter the system. This created the rough idle, misfires, and power loss you described. Engine performance was significantly affected, and the problem worsened over time. The repair required complete manifold replacement, as the scorching had compromised the material integrity. This was a serious issue that needed immediate attention, as continued operation could have led to further engine damage and potentially unsafe driving conditions. Your symptoms mirror my experience exactly, particularly the stalling at idle and exhaust smell. These are classic signs of manifold problems affecting the air-fuel mixture. The high mileage on your vehicle puts it in the typical range where these issues can develop. A proper diagnosis should include pressure testing and visual inspection of the manifold for cracks or warping. Consider having the manifold sensor checked as well, as it could be contributing to the problems.

Thanks for sharing your experience with the intake manifold issue. My symptoms were nearly identical on my Audi A8. The engine misfire and rough running were quite concerning. The mechanic found a gasket leak between the manifold and cylinder head, which was causing unmetered air to enter and mess up the fuel mixture. Have the issues stayed resolved since your repair? Also curious what the total cost ended up being for the manifold replacement and associated work? My repair bill was substantial but worth it to prevent further engine damage.

After getting the intake manifold fixed due to the severe scorching, my A6 has been running perfectly for the past 8 months. The engine misfire issues completely disappeared, and the rough running is now a distant memory. The repair cost came to 1180 Euro for parts and labor, which included replacing the damaged manifold and addressing the gasket leak. The improvement in performance was immediate, no more jerky acceleration or concerning air intake problems. The car manifold pressure is now stable, and the engine runs smoothly even at idle. The repair shop did a thorough job testing the system afterward to ensure there were no remaining leaks or pressure issues. While the cost was significant, preventing further engine damage made it a worthwhile investment. Early intervention with manifold issues is crucial, as letting them persist can lead to more extensive and expensive repairs down the line.

I finally got my A8 fixed last week. After reading about your similar experience, I took it to a new mechanic who specializes in German cars. The inspection confirmed a cracked manifold and failing gasket, exactly as suspected. The repair process took two days but the results were worth the wait. The engine performance improved dramatically after the repair. No more check engine light, the idle is smooth, and the power has been fully restored. The manifold pressure readings are now within normal range and the exhaust smell is completely gone. Total cost came to 1450 Euro including parts, labor, and a new manifold sensor they recommended replacing while everything was apart. The price was steep but reasonable considering the work involved. The shop was great about explaining the entire process and showed me the damaged parts. Much better experience than my previous mechanic who kept dismissing the symptoms. Thankful to have found a reliable solution before the problem caused more serious engine damage.