Passat Hybrid Throttle Issues Causing Rich Fuel Mix

I had a very similar issue with my 2014 VW Golf GTE hybrid last year. As someone with some mechanical experience working on hybrids, I can share what worked for me. The symptoms matched exactly what you describe, poor fuel efficiency and rough engine idle, especially during cold starts. Initially, I suspected a dirty throttle valve, but after visiting my regular workshop, they diagnosed a defective accelerator pedal module. The repair took about 2 hours and cost 205€, including parts and labor. Since the fix, the throttle position sensor readings have been spot-on, and the engine idle returned to normal. Fuel consumption also dropped back to expected levels. Before jumping to conclusions though, could you share: Current mileage on your Passat? Are you getting any specific error codes? Does the throttle response feel sluggish or jerky? Have you noticed any warning lights on the dashboard? These details would help determine if your issue matches what I experienced. Sometimes throttle-related problems can have similar symptoms but different root causes in hybrid systems.

Had 3 mechanics look at my car with similar symptoms. Engine idle was extremely rough until the throttle body was completely replaced, not just cleaned. The throttle valve was actually stuck, causing erratic fuel efficiency. At 111112km and after my latest service, the issue returned briefly but was resolved with a thorough throttle position sensor calibration. Much cheaper fix the second time around, 180€ versus the initial 650€ replacement. Running perfectly now with normal fuel consumption, but recommend getting the throttle assembly checked as preventive maintenance. Might save you from more expensive repairs down the line.

Interesting you mentioned the throttle position sensor calibration, that actually matches my experience too. After my initial accelerator pedal module repair on my Golf GTE, I also had a brief return of symptoms around the 120000km mark. The air intake and throttle body assembly definitely need regular attention on these hybrids. My mechanic explained how the engine idle issues are often connected to carbon buildup affecting the throttle valve operation. After cleaning and recalibrating the throttle position sensor, my fuel efficiency returned to normal levels. One tip: I now make it a point to run the engine at higher RPMs occasionally to help prevent carbon deposits from building up in the throttle body. Since doing this regular preventive maintenance, I haven't had any more issues with rough starts or poor engine throttle response. Your repair costs sound about right for this type of work. Smart move getting it properly diagnosed rather than just throwing parts at the problem.

Thanks for confirming the throttle position sensor calibration fixed the recurring issue. Good to hear that a proper calibration at 180€ solved it without needing another full replacement. The initial 650€ for the throttle body replacement was worth it since the valve was actually stuck. My car runs great now at 111112km with normal fuel efficiency restored. Really glad I had the throttle body issue properly diagnosed instead of trying quick fixes. Running the engine at higher RPMs occasionally sounds like solid advice to prevent carbon buildup affecting the throttle valve. Will definitely keep up with preventive maintenance checks on the air intake system and throttle assembly from now on. Much rather catch these issues early than face another major repair. The car throttle response is perfect now and starts are smooth again, exactly how a hybrid should perform.