Atlas Power Loss and Smoke, Knock Sensor Alert

Had similar symptoms on a 2017 VW Tiguan. The engine knock and power loss turned out to be serious carbon deposits in the combustion chamber, affecting the ignition timing significantly. The pre-ignition issues caused cylinder heads to develop hot spots, leading to that exact jerking sensation during acceleration. The smoke was a clear indicator of incomplete combustion. Initially suspected a failing knock sensor, but diagnostic testing revealed extensive carbon buildup on intake valves and piston crowns. The repair required thorough chamber cleaning and recalibration of ignition timing. Piston slap was also detected during the inspection, which explained the metallic noise at cold starts. The fix involved decarbonizing treatment, replacing spark plugs, and programming the ECU to adjust timing. This is typically a 1-2 day repair job at a qualified shop. Left untreated, carbon deposits can cause permanent engine damage. Would recommend getting it checked soon, focusing on: Combustion chamber inspection, Knock sensor testing, Compression test, Intake valve examination These symptoms should not be ignored as they can lead to more severe engine problems.

Thanks for sharing your experience with the Tiguan issues. Seeing very similar patterns with my Atlas right now, especially that jerking during acceleration. Really helpful to know about the carbon deposits since I was fixated on just the knock sensor. Going to have it checked this week. Did you remember roughly what the total repair cost was? Also curious if youve had any recurring detonation issues since the fix?

Good to follow up on your Atlas concerns. Since getting my Tiguan fixed, the knocking combustion issues completely disappeared. The thorough cleaning of carbon deposits in the combustion chamber resolved all symptoms, no more jerking, power loss, or smoke problems. The total repair came to 425€, which included the decarbonizing treatment and recalibration of the ignition timing. Its been running smoothly for over a year now, with no signs of detonation or pre-ignition. The fuel octane requirements stayed the same, but engine performance notably improved. Quick tip: regular maintenance and using quality fuel helps prevent these deposits from building up again. My engine has been knock-free since the repair, confirming the diagnosis was spot on. If your symptoms match what I experienced, focusing on the combustion chamber cleaning should resolve the issue.

Thanks everyone for the detailed feedback. Finally got my Atlas checked out yesterday and you were right about the carbon deposits. The mechanic found significant buildup in the combustion chamber causing the engine knock symptoms. The full service included a complete decarbonizing treatment, new spark plugs, and ECU timing adjustment. Total cost came to 490€ but worth every cent. The engine tuning made a huge difference, no more jerking or power loss during acceleration. They showed me the carbon deposits they cleaned out and it was shocking how much had accumulated. The mechanic recommended switching to higher octane fuel to help prevent future buildup. Already notice smoother acceleration and no more smoke issues after just one day. Really glad I got this sorted before any serious engine damage occurred. Will definitely stay on top of maintenance to avoid similar problems in the future. The detonation problems are completely gone now and the engine runs like new again.