S7's Rough Idle and Fuel Issues Point to Throttle Body

Experienced the same symptoms on my 2020 S5 last winter. The car throttle response was erratic, causing inconsistent idle and decreased fuel efficiency. Initially suspected a simple throttle body cleaning would fix it, but diagnostic testing revealed a faulty electronic throttle control valve. The engine throttle system needed a complete module replacement, not just cleaning. The symptoms matched exactly, rough starts, unstable idle, and notably higher fuel consumption. This was a serious issue that required immediate attention, as it could potentially lead to complete throttle failure. The repair involved replacing the entire throttle body assembly with its electronic control unit. After replacement, the idle smoothed out completely and fuel consumption returned to normal levels. This is not a DIY job due to the complex calibration required after installation. For an S7 with those symptoms, recommend getting it properly diagnosed at a certified shop. The throttle body system in these models is electronically integrated, and temporary fixes like cleaning rarely solve the underlying issue when these symptoms appear together.

Thanks for sharing your S5 experience. This was exactly what I needed to hear since my symptoms match perfectly. The throttle position problems and inconsistent idle are really starting to worry me. Quick question, do you recall the total repair cost for your throttle body replacement? Also, has everything stayed smooth with your throttle control valve since the fix? Just trying to budget accordingly and make sure this is a lasting solution before I book it in.

Had the work done and happy to report my throttle control valve issues are completely resolved. The total came to 205 Euro for fixing the defective accelerator pedal module, which was actually less than expected. Since the repair, the air intake and fuel efficiency have returned to normal levels. The car throttle response is now perfect, no more rough starts or inconsistent idle. This repair happened 8 months ago and everything has stayed working perfectly since then. The investment was worth it as the engine now runs as smoothly as when it was new. The technician confirmed the throttle cleaning alone wouldn't have fixed it, replacing the faulty components was the only real solution. My advice would be to get it done sooner rather than later as these issues tend to worsen and could affect other engine components if left unchecked.

After getting multiple recommendations, I finally took my S7 to a certified shop last week. The diagnostic confirmed what others suggested, a faulty throttle body assembly was causing the unstable engine idle and poor fuel economy. The mechanic found the electronic throttle control was malfunctioning, requiring a complete replacement rather than just cleaning. The total repair came to 850 Euro, which included parts and labor. While not cheap, it was worth every cent. The difference is night and day. The car throttle response is crisp again, starts are smooth, and fuel consumption has dropped back to normal. Best of all, that annoying inconsistent idle is completely gone. Really glad I addressed this before it could cause additional engine problems. For anyone else facing similar symptoms, dont waste time with temporary fixes. Get it properly diagnosed and repaired by a certified technician who knows these systems.