VW Lupo Throttle Body Causing Delayed Acceleration

Had the exact same symptoms on a 2001 Polo 1.4L. The throttle response delay kept getting worse until the car went into limp mode. The check engine light came on during highway driving. The issue turned out to be a failing throttle body position sensor. The electronics inside had degraded over time, causing inconsistent readings to the ECU. This made the air intake system behave erratically since the computer could not determine the correct throttle position. The repair required a complete throttle body replacement as the sensor is integrated and cannot be replaced separately. After installation, the shop had to perform an electronic throttle relearn procedure using diagnostic equipment. This was a serious repair that required specialized diagnostic tools and programming. The car ran perfectly after fixing it and the check engine light never came back. The symptoms you describe match exactly what happened, sluggish acceleration and inconsistent throttle response are classic signs of a failing throttle body on these engines. Would recommend having it properly diagnosed with a scanner before replacing parts. The throttle position sensor fault code should show up in the diagnostic readout if this is indeed the issue.

Thanks for the detailed reply about your Polo repair. I am having those exact symptoms with my Lupo now, the erratic engine idling and poor throttle response are really concerning. The throttle sensor replacement you mentioned sounds like what I need. Since you went through this already, do you remember the replacement cost for the complete throttle body job? And has everything stayed working properly after the fix?

Since my initial post about the Polo repair, I got the fix done last week. The throttle valve was indeed defective and causing poor air flow and inconsistent engine response. The repair shop found the accelerator pedal module was also faulty, which added to the total cost. The final bill came to 265€ for fixing the electronics in the accelerator pedal module. This was actually less than expected given the diagnostic work needed. The car runs perfectly now, no more engine idling issues or check engine lights. The throttle response is crisp and immediate, just like when the car was new. If your symptoms match what I described, getting it checked soon is important before it goes into limp mode. A proper diagnosis with scanner tools will confirm if you have the same underlying issue. The repair has completely resolved all the problems I mentioned in my first post. No regrets about getting it fixed professionally rather than trying cheaper alternatives.

Thanks for following up. I took your advice and had my Lupo checked at a different mechanic this time. The diagnostic scan confirmed the throttle sensor was failing, exactly like you described. The repair cost came to 320€ including parts and labor. A bit more than your repair but worth every cent for the peace of mind. The mechanic also cleaned the throttle body while it was out, which helped improve fuel efficiency. What a difference in performance now, the throttle response is instant and smooth. No more check engine light or hesitation. The air flow readings are stable according to the scan tool they showed me. Really glad I asked here before trying another quick fix. The proper diagnosis and repair saved me from throwing parts at the problem like my previous mechanic would have done.