VW Phaeton Diesel Rough Idle and Acceleration Issues

Had similar symptoms on my 2006 VW Touareg V10 TDI. The rough idle and jerking during acceleration turned out to be a combination of issues with the exhaust system and oxygen sensor. The stored error code was pointing to the oxygen sensor, but the real problem was more extensive. The exhaust leak was causing incorrect readings from the oxygen sensor, which made the engine computer adjust the fuel mixture incorrectly. This created a chain reaction affecting overall performance. A thorough inspection revealed cracks near the manifold connections and deteriorated gaskets. The repair required: Replacing the faulty oxygen sensor, Fixing the exhaust leaks, Installing new gaskets, Checking the crankshaft sensor connections This was a serious issue that needed immediate attention because exhaust leaks can damage other components and affect engine performance. The symptoms got significantly worse over time, especially during cold starts. Worth checking these components in this order: 1. Exhaust system for leaks 2. Oxygen sensor readings 3. Crankshaft sensor 4. Fuel system pressure Since your Phaeton has similar age-related wear patterns, these areas would be logical starting points for diagnosis.

Thanks for sharing your experience. I dealt with almost identical issues on my Phaeton last winter. The rough idle was particularly bad during cold starts, and the fuel injectors turned out to be the main culprit. After cleaning and recalibrating them, most issues cleared up, though we also found a failing ignition coil during the diagnosis. How much did your repair end up costing? Also curious if you had any recurring issues since getting it fixed? Would help to know if I should expect any other related problems down the line.

After the repair work was completed, the uneven engine running completely disappeared. The exhaust leak repair cost 265€, which included replacing worn gaskets and fixing the cracked sections near the manifold. The mechanic did a thorough job addressing all connection points in the exhaust system. Since fixing the leak, the engine misfire issues and rough idle have not returned. The oxygen sensor readings are now accurate, and the engine computer can properly adjust the fuel mixture. The investment was worth it, as preventing further damage to other components likely saved money in the long run. Your experience with the fuel injectors is interesting, sometimes these symptoms can have multiple causes. Regular maintenance of components like spark plugs and air filters helps prevent similar issues from developing. My advice would be to keep monitoring for any unusual sounds or vibrations, but with proper repairs, these problems typically dont recur.

Thanks for the input. I finally took my Phaeton to a different mechanic who actually knew what they were doing. The engine misfire symptoms were spot on with what you described. They found the oxygen sensor was completely shot and two spark plugs were worn beyond specs. The repair came to 420€ total including parts and labor. They also cleaned the fuel injectors while they were at it since they were a bit gunked up. Car runs like new now, no more jerking or rough idle issues. The check engine light cleared up right after the fix. Would have saved time and money if I had gone to this shop first instead of wasting cash at that other place. Worth noting that the crankshaft sensor checked out fine during testing. Really glad to have this sorted before winter. The cold starts were getting pretty rough and I was worried about causing more damage. Keeping up with regular maintenance from here on out.