VW Up Misfiring and Rich Fuel Mix Causing Power Loss

Had the same symptoms on my 2014 VW Polo TSI last year. The main issue turned out to be faulty fuel injectors causing an incorrect air-fuel ratio. The symptoms matched exactly, rough running, power loss, excessive fuel consumption, and engine warning light. The fuel injectors were not atomizing the fuel properly, leading to uneven combustion. This caused the engine management system to compensate by adding more fuel, making the mixture too rich. The issue was affecting the catalytic converter as well due to unburned fuel. The repair involved: Testing all fuel injectors, Replacing 2 defective injectors, Cleaning the air filter system, Resetting engine management, Running diagnostics to confirm proper operation This was a serious repair that needed immediate attention as bad injectors can cause long-term engine damage and increased emissions. After the fix, fuel economy returned to normal and the engine ran smoothly again. For your VW Up, these symptoms strongly suggest injector issues. Best to have it diagnosed soon using proper diagnostic equipment to prevent further complications.

Thanks for sharing your experience. Your description matches my symptoms perfectly. My VW Up also showed those exact issues, jerky acceleration and the oxygen sensor readings indicated a rich mixture. After reading about your injector problems, I had mine checked. The mechanic confirmed similar issues but in my case only one injector needed replacement, along with a clogged air filter that was making the air-fuel ratio even worse. Were you able to keep track of the repair costs? Also curious if you had any related problems show up since the fix? My fuel economy has improved dramatically after the repair but want to make sure I keep an eye out for potential follow-up issues.

Glad I could help identify the problem. After fixing my injector issues about 8 months ago, paying 515€ for the complete repair including labor, my car has been running perfectly. The engine management system now maintains the correct air-fuel ratio, and the oxygen sensor readings are spot-on. The mechanic did a thorough job testing the fuel injection system and replacing the faulty injector. The spark plugs were also checked to ensure optimal combustion. Since the repair, my fuel economy has stayed consistently good, back to what it should be for this model. No related issues have emerged since. The engine runs smoothly without any of the previous symptoms. Regular maintenance and keeping the air filter clean should prevent similar problems from developing again. The investment was worth it to prevent potential long-term engine damage.

Thanks everyone for the advice! After getting my car fixed last month, I wanted to share how it went. The mechanic charged 320€ total, less than expected since only one fuel injector needed replacement. The check engine light issue cleared up right after they cleaned the system and installed the new parts. The best part is my car feels like new again, no more jerking during acceleration and fuel consumption is back to normal. The oxygen sensor readings are now stable and the rich mixture problem is completely resolved. When they tested the spark plugs everything looked good, so that saved some money too. Really glad I investigated this early before it could cause bigger engine problems. Definitely learned my lesson about regular maintenance. Will keep monitoring things but so far running perfectly after 3 weeks of daily driving.