RS4 Throttle Body Issues Causing Major Power Loss

Had a similar issue on my 2018 RS5 last season. The symptoms matched exactly, reduced power, engine idling problems, and inconsistent throttle response. The root cause was a failing accelerator pedal position sensor, not the throttle body itself. This affected both the air flow and fuel efficiency significantly. The system was defaulting to a safety mode, which explained the sluggish performance. The repair required replacing the entire accelerator pedal module as the electronics inside were defective. It was a serious issue that needed immediate attention since it impacted safe vehicle operation. The air intake and engine management systems heavily rely on accurate pedal position data. After the repair, the engine idling returned to normal and the power response became immediate again. The check engine light cleared and has not returned since. The job took about 3 hours at the shop. Important: Have a proper diagnostic scan done. The throttle position sensor and accelerator pedal module issues can show similar symptoms, but replacing the wrong part wont solve the problem.

Thanks for sharing your experience. It sounds very similar to what happened to my Audi RS4 last year. The limp mode and response delay issues were exactly what I dealt with. Did the repair hold up well since then? Just curious about any recurring problems, as Im weighing whether to just replace both the throttle sensor and pedal module at once to prevent future issues. Also, do you recall the replacement cost for the pedal module? Mine is starting to show the same symptoms again and Id like to budget accordingly.

Since getting the accelerator pedal module replaced last season, the car has performed flawlessly with no return of the limp mode or response delay issues. The repair cost was 265 Euro which included labor and parts. The air intake and throttle response remain perfect after the fix. I would not recommend replacing both components unless diagnostics indicate both are failing. A proper diagnosis showed the throttle valve was functioning correctly in my case, the problem was solely the defective electronics in the pedal module. The engine idling is now stable and the check engine light has stayed off since the repair. If your symptoms are returning, get a diagnostic scan first to pinpoint the exact failing component rather than replacing parts unnecessarily. The fix was definitely worth the cost considering how much it improved overall performance and restored proper engine operation. Going straight to the root cause saved money compared to replacing multiple parts.

Thanks everyone for the helpful replies. After visiting my mechanic last week, the diagnosis confirmed it was indeed the accelerator pedal module causing the issues. Got it replaced for 280 Euro and the car runs perfectly now. The limp mode and sluggish response completely disappeared after the repair. My mechanic also cleaned the throttle body while doing the work, which helped improve the air flow and idle stability. The whole job took about 4 hours but was worth every cent. The check engine light cleared right after and hasnt come back. The throttle sensor readings are now stable according to the diagnostic report. Really glad I got this fixed before it led to bigger problems. Appreciate all the advice that helped point me in the right direction.