VW Atlas Throttle Issues Impact Performance & MPG

Had a very similar issue with my 2021 VW Tiguan diesel last summer. Have some experience working on VWs but always trust certified mechanics for electronic issues like this. The symptoms matched exactly, poor throttle response, increased fuel consumption, and hesitation during cold starts. Initially thought cleaning the air intake and throttle valve would solve it, but diagnostic tests revealed a defective accelerator pedal module. Took it to a workshop where they ran complete diagnostics on the engine throttle system. The car throttle position sensor readings were inconsistent, which explained the erratic behavior. The entire repair including parts and labor came to 205€. Workshop had it done in about 3 hours. The fix completely resolved the issues, fuel economy returned to normal and the sluggish starts disappeared. For your Atlas, I would recommend getting the throttle position sensor and accelerator module checked first. Could you share: Current mileage on your Atlas? Any check engine lights or error codes? Have you noticed any changes in idle behavior? When was the last time the air intake system was serviced? This information would help determine if you are dealing with the same underlying issue.

Just had my last service at 51981km. After taking it to a certified workshop yesterday, they confirmed your suspicion about the throttle control valve being the culprit. Their diagnostic showed the engine idle was unstable and throttle position readings were off. The mechanic recommended a thorough throttle body cleaning first before considering replacement. They found significant carbon buildup affecting proper operation. After cleaning, the car throttle response improved significantly and fuel consumption is back to normal levels. The total service cost including diagnostics and cleaning came to 180€ with about 2 hours labor time. So far, no error codes have appeared and the engine idle feels smooth again. Will monitor the situation and report back if anything changes.

Thanks for the update on your Atlas. Glad to hear the throttle cleaning resolved the issues without needing expensive parts replacement like in my Tiguan case. That carbon buildup you mentioned is exactly what can throw off throttle position readings and affect fuel efficiency. The fact that your engine idle has stabilized after cleaning suggests it was indeed just accumulated deposits rather than a failing sensor or module like I experienced. Since we both drive VW diesels, preventive throttle cleaning might be worth considering every 40000-50000km. My mechanic mentioned these engines are somewhat prone to carbon deposits affecting the throttle body. Keep monitoring your fuel efficiency and throttle response over the next few weeks. If you notice any regression back to rough idle or poor starts, it could indicate a deeper issue with the throttle position sensor like I had. But based on the improvement you described, sounds like the cleaning was the right call in your case. For ongoing maintenance, using high-quality fuel and avoiding excessive short trips can help minimize carbon buildup in the throttle system. These simple habits have helped maintain smooth engine throttle operation in my Tiguan since the repairs.

Thanks for the excellent advice about maintenance intervals. Yes, the throttle cleaning really did the trick for my Atlas. The air intake system and engine idle are working perfectly now after the service. Following your suggestion, I will definitely schedule regular throttle cleaning around the 45000km mark going forward. Makes sense to be proactive rather than waiting for throttle position issues to develop again. The mechanic also recommended using premium diesel fuel to help reduce carbon deposits. Since the cleaning, I have been filling up with higher grade fuel and noticed the car throttle response stays consistently smooth. Will keep monitoring the performance and fuel consumption over the next few weeks. So far everything is running great, starts are quick, idle is stable, and economy is back to normal. Really appreciate the helpful insights from your similar experience.